D&D 5E Basic Build Series: Warlock

Author: Tatersalad810

The Warlock is designed to be a dual purpose blaster and controller. Warlocks have access to the premier damage cantrip eldritch blast, and the class is effective at complementing its baseline damage output with battlefield control and utility via spell choices and Eldritch Invocations. The Warlock spell list has a number of potent and all-purpose standouts, but the mechanics of the class allow for the selection of several niche and/or situational options as well, which may be skipped or passed over by other full casters. A Warlock adds additional flexibility to a party that can ease some pressure on other full casters. This build, part of our Basic Build Series, combines the fiery Fiend patron with the Pact of the Chain.

Race: Human (Variant)

Ability Score Increases – +1 Con, +1 Cha. 
Feat – Moderately Armored (+1 Dex). One of the weaknesses of the Warlock class is its defenses. With only light armor and no shield proficiencies, and no access to the shield spell that Wizards and Sorcerers get, a Warlock is likely to be sitting on at most 15 AC indefinitely without help. Fortunately, unlike Wizards and Sorcerers, we qualify for the Moderately Armored feat, which will eventually allow us to bump our AC up to 19 with half plate and a shield. That’s a lot of value from a single feat, and it increases our Dexterity by 1 to boot.
Skill – Perception. Having a good Perception is nice for finding traps, hidden enemies, ambushes, etc.
Languages – Common and Abyssal. Abyssal is an exotic language and requires the permission of the DM to obtain, but you’re a Warlock of the Fiend, and this is one of the most flavorful languages to learn for your class.

Class: Warlock

Skills – Arcana, Deception. Arcana is perhaps the most useful “knowledge” skill for the vast amount of magic phenomena a D&D party regularly encounters, and Deception is a commonly used skill based on Charisma.
Otherworldly Patron – Fiend. This subclass provides us unique offensive capabilities through spells that would be hard to come by otherwise.
Expanded Spell List (Fiend feature) – We will not be using the majority of the options here, but there are a couple standouts in it that will really augment our firepower and value in the limited spell slots we have.
Dark One’s Blessing (Fiend feature) – Find a bat or some other unfortunate creature early in the morning and blow them up with eldritch blast to start off the day with some nice temporary hit points. Some DMs are more stingy with what they consider to be a “hostile creature” so talk to them first about if this works. Otherwise, this just generates some extra buffer for you throughout the day. Don’t forget about it!
Pact Magic – Our spell slot progression is unique and recharges on a short rest. This will impact our spell selection as we want either spells that get the most bang for their buck, or spells that are situationally great but costly for other full casters to use. If your party does not take short rests at all, or has never taken a second short rest in a day, do not play a Warlock. Warlocks have a limited number of spells known compared to the rest of the full spellcaster classes. As a result of this and our Pact Magic feature we will be constantly swapping out our spells when we level up to maximize value when we cast a spell and use one of our precious spell slots.

Command – Decent spell with good upcasting, wastes an enemy action or more than one if you order it to flee and it has no ranged attacks. Can cause opportunity attacks if your melee allies are positioned properly with this. 
Hex – Hex is a decent damage buffer and can last multiple combats. When you use hex be sure to consider your allies and their toolkit with respect to the check. Targeting strength checks could make an entangle cast by a Druid ally last longer on things that failed the initial saving throw or a Fighter’s grapple more effective. At level three this will work well with a friendly web or phantasmal force. Use it on targets that need to die quickly of course, but keep in mind that rider against checks can be potent in the right scenarios and your allies will appreciate you.
Eldritch blast – The staple cantrip of Warlocks. The damage type is rarely resisted, great range, highly customizable with Invocations; this is your bread and butter when you are not casting spells. 
Minor illusion – Versatility limited chiefly by imagination and in some cases, DM fiat.

Ability Scores

8 Str, 13+1 Dex, 15+1 Con, 8 Int, 12 Wis, 15+1 Cha

Background (Custom)

Skills – Persuasion, Stealth. Persuasion helps us be the party face in public. Stealth is very handy for dungeon exploration and surprising monsters.
Tools – Thieves’ tools. 
Languages – Infernal. You’re a Guild Artisan and the go-to person of your guild when it comes to occult knowledge and deciphering fiendish runes. Like Abyssal, this is another flavorful language, but it really can be anything you want. Bear in mind Abyssal is important for summon greater demon.
Feature – Guild Membership: Lodging and food if necessary, and a source of potential patrons, allies, or hirelings.
Creator’s Note – Making a custom background is RAW. The PHB on page 125 states, “The sample backgrounds in this chapter provide both concrete benefits (features, proficiencies, and languages) and role playing suggestions. To customize a background, you can replace one feature with any other one, choose any two skills, and choose a total of two tool proficiencies or languages from the sample backgrounds.” Using this, we are making a custom background and using the Guild Artisan feature.

Equipment

Warlock Starting Equipment

• Light crossbow with 20 bolts. Ranged attacks are good, so let’s take a crossbow. Our crossbow will be our main source of damage until we can afford a shield, which we buy as soon as we can.
• Component pouch. Since you’ll be using a shield, using an arcane focus now may impair your ability to perform somatic components. If your DM uses a house rule that requires you to scavenge for the right components, use an Arcane Focus instead. Better still, buy both and a bunch of back up pouches later on. 
• Dungeoneer’s pack
• Leather armor, a quarterstaff, and two daggers

Guild Artisan Background Starting Equipment

• A set of thieves’ tools
•  letter of introduction from your guild
•  set of traveler’s clothes
•  belt pouch containing 15 gp

Purchasing Goals

• A bullseye lantern to illuminate enemies in dark areas as we lack Darkvision.
• A shield, chain shirt, breastplate, half-plate. If you have the funds available to skip one of the armors, then by all means skip it. We’re aiming for the armors that don’t cause disadvantage on Stealth rolls until we get to half-plate.
• Healer’s kit, potions of healing.

Level 1 Strategy

Hang out in the back with cover preferably and use your crossbow, since you don’t get the Armor Class bonus from your shield if you’re using a crossbow. Your crossbow does higher average damage than eldritch blast at this point because we haven’t picked up Agonizing Blast yet. Use your spells only when needed. Cast eldritch blast if your DM pits your party against something that resists normal weapons.

Level 2 Warlock

Eldritch Invocations – Agonizing Blast, Repelling Blast.
Agonizing Blast – Adding our Charisma modifier to eldritch blast now means the cantrip does more damage than our light crossbow and is now our main source of damage.
Repelling Blast – Forced movement without a saving throw is huge. The combat utility of this cannot be overstated. Blast an enemy over a bridge or a ledge. Blast an enemy into an environmental hazard. Blast a ghoul charging your party and force a Dash action. Blast a zombie out of melee range of your caster ally away so your ally can run without having to Disengage. Blast a wolf out of the Polearm Master Fighter so they get another opportunity attack next time it approaches. Also this is guaranteed to break a grapple if you choose to use it, so keep that in mind.  
Spell changes: +armor of Agathys.

Armor of Agathys – Decent spell, provides some defense with the temporary hit points, provides some punishment when hit in the form of cold damage. Use this when you’re unexpectedly in melee with no temporary hit points from Dark One’s Blessing. Remember that temporary hit points don’t stack. All this together means this is too niche so we’ll be happy trading it out next level.

Level 2 Strategy

Sell the crossbow and start controlling the battlefield with your eldritch blast. Push things into hazards with Repelling Blast. If a battle looks tough, use one of your spells to give you a little bit of extra durability, damage, or utility.

Level 3 Warlock

Pact Boon – Pact of the Chain. Now that we get to pick one of four Pact Boons for our class, we’ll be taking Pact of the Chain because the extra utility brought by the familiar summoned with this feature will help our dungeon exploration as well as our combat experience.
Pact of the Chain – Alright, let’s get an imp familiar. Imps have several awesome features that we’ll be using very frequently. Flight is obviously important as we can more safely explore caverns and rooms while flying out of melee range. Invisibility and a +5 to Stealth rolls means our familiar buddy is less likely to be noticed when scouting. The real kicker for Invisibility is it only ends when the imp attacks or loses concentration, so it can give the Help action in combat and attacks against them have disadvantage. Additionally, anything it carries is invisible too, so ball bearings, caltrops, dynamite, or other gear that would slow down or annoy the enemy can be used without becoming visible; remember it can carry up to 45 lbs of stuff. We do not want our familiar to take the Attack action right away because that requires us to use our action. Devil’s Sight (the imp feature, not an Invocation) is obviously useful for scouting, and Magic Resistance means our familiar is less likely to die in combat. Remember that you can choose a different familiar each time you cast find familiar, so know what the other options can do and be mindful you can switch to them should a situation arise where other options would be preferable.
Spell changes: +invisibility, +misty step, +find familiar, –armor of Agathys.

Invisibility – Invisibility is a situationally useful spell but very useful in the appropriate situations. Unfortunately, most casters will skip this spell for better or more universally applicable spells, but since our slots come back on a short rest, we can afford to pick it up without losing out on our spell slots for the entire day.
Misty step – This is your spell to escape enemy grapples and get out of melee without having to disengage to fully retreat. Very important insurance policy to have. It also helps us escape a web or a wall of force.
Find familiar – Via Pact Boon. 

Level 3 Strategy

The plan here is largely the same as with level two, but now you have an imp that can administer the Help action, administer potions, and do all the wonderful things a normal familiar does as well. Your allies may have spells that cause area of effect damage or area denial by now; use your eldritch blast to push the enemies around and set your fellow party members up for a very effective turn. Melee only enemies can be pushed back and be forced to waste a turn Dashing, which is great value.

Level 4 Warlock

Ability Score Improvement – +2 Cha. Buffing our Charisma increases our chance to hit and raising our spell save DC for the very nice options we get at level 5.
Spell changes: +darkness, +shatter, +mind sliver, -hex.

Darkness – Be careful with how you use this spell as it’s possible to cause your allies some frustration. Use it when you’re fighting enemies that have Pack Tactics or other ways to generate advantage like wolves, kruthics, krauls, kobolds, Karrnathi undead soldiers, and various humanoids. Removing their sight imposes disadvantage and cancels any advantage, but again, don’t grief your party. Certain spells like magic missile and hold person require vision of the target to use and this counters those spells completely.
Shatter – This is an okay spell which we’ll be using to blast when several low HP enemies are clumped together. Use sparingly. This spell emits ‘a sudden loud ringing noise’, which some DMs may rule attracts the attention of other hostiles deeper in the dungeon. which can work for or against your game plan.
Mind sliver – Combo this with another ally spellcaster who is casting a control spell like web or levitate on a big threat to make sure they fail the saving throw.

Level 4 Strategy

No more hex? Are you out of your minds, Tabletop Builds? Believe it or not, you don’t need it. We already have a number of more impactful uses for our limited spell slots. Massive explosions. Diabolically powerful concentration spells. If you short rest so infrequently that hex is preferable to these spells simply because it’s decent to concentrate on all day, you should look to talk with your DM and party about the importance of a few short rests in a day. If that doesn’t work out and you are stuck with 2 spells per day until level 11, Warlock was probably not the best choice for the campaign you are in.

Level 5 Warlock

Pact of the Chain – With an additional Eldritch Invocation this level, we switch from primarily using an imp familiar to a sprite familiar. Sprites have several awesome features that we’ll be using very frequently. Flight is obviously important as we can more safely explore caverns and rooms flying out of melee range. Invisibility and a +8 to Stealth rolls means our familiar buddy is less likely to be noticed when scouting. Again, the real kicker for Invisibility is it only ends when the sprite attacks or loses concentration, so it can give the Help action in combat and attacks against them have disadvantage. Additionally, anything the sprite carries is invisible too, so ball bearings, caltrops, dynamite, or other gear that would slow down or annoy the enemy can be used without becoming visible. What’s really nice as well is the shortbow and conditions attached to it. Poisoned is a good debuff in almost all combats and the lack of repeat saving throws on this makes it a solid choice. Unconscious will almost never come into play as the text states if the total of the roll is 5 or lower, thus not receiving the benefit of our spell save DC. Heart Sight should be used on every NPC you meet, if possible. You never know when you’re talking to someone/thing nefarious or with ulterior motives. If it’s a celestial, fiend, or undead disguised, good job: you figured it out automatically.
Eldritch Invocation – Agonizing Blast, Investment of the Chain Master, Repelling Blast.
Investment of the Chain Master – Now we’re cooking with some spices! Our sprite will likely be invisible and hidden at the start of combat scouting around and doing sprite things. On round one we can use our bonus action to have them attack with advantage, and the poison DC is now your spell save DC. Some enemies may boast higher CON saves, but you can do this every turn and if they fail even once, the poison will remain for the entire encounter. If for whatever reason you really need to poison someone you can use your action and forgo one of your attacks so the sprite can use its reaction to shoot someone, and then order it to shoot again on its turn with your bonus action.
Spell changes: +fireball, +hypnotic pattern, -shatter.

Fireball – You know what this is and you know how it works. Limited time offer: enjoy your fireball slots returning on a short rest. See Fiend patron for details! Bear in mind fireball isn’t always the answer, but in most scenarios (at this level) it’s a very good one.
Hypnotic pattern – This is one of the best spells for its level in the game, becoming our biggest play in hard fights. It incapacitates and immobilizes creatures in a 30’ cube who fail a Wisdom save, and they don’t get any additional saves in subsequent turns. Their allies can use an action to break them out of it, but even if they do, that’s more creatures doing things with their turns that aren’t attacking you. The biggest limitation of this spell is that it doesn’t work on creatures immune to being charmed. Having this spell on short rest is nice, and it also has no verbal component, so keep that in mind if you’re hit with a silence or something.

Level 5 Strategy

Welcome to tier two of Warlock play where the fun really takes off. We now have two incredibly potent spells that wreck encounters at this level. Judge your encounters and try to figure out if you need to use any big guns or if you can handle the hostilities with your eldritch blast that now generates two beams, so you deal twice as much damage and can push two different enemies with Repelling Blast or push one back up to twenty feet—very cool. Your slots do recharge on a short rest, so don’t be afraid to use one if you’re unsure how difficult the enemies are. Your familiar should be invisible and hidden at the start of every combat for advantage on their first shortbow shot and then behind cover until their turn again on subsequent rounds unless they’re attacking after you issue your bonus action command. 

Level 6 Warlock

Dark One’s Own Luck (Fiend feature) – Use this on saving throws. Now that you have awesome spells, enemies will try to break your concentration, and this is a handy dandy method to protect our concentration. Neat.
Spell changes: +counterspell, +thunder step, -misty step.

Counterspell – Using one of your two precious spell slots on a counterspell is rarely going to feel good, but eating an enemy’s fireball/web/slow/hypnotic pattern/etc. is absolutely going to feel worse. Don’t save your slots to make sure you can cast this on demand but don’t hesitate to use it when you know something nasty is coming your way. This spell auto-upcasts as our slot level increases, which is very nice.
Thunder step – It’s like misty step, but better. Action vs bonus action cast isn’t fun but grabbing an ally and teleporting them away from that troll that’s grappled them is great fun. The damage is ok, but it’s not why we’re taking it.

Level 7 Warlock

Eldritch Invocation – Agonizing Blast, Investment of the Chain Master, Repelling Blast, Voice of the Chain Master. 
Voice of the Chain Master – We’ve got some good invocations we want in order to be effective in combat, so let’s give our familiar some additional utility and better scouting.
Spell changes: +dimension door, +summon greater demon, -thunder step.

Dimension door – It’s like thunder step, but the range is better, you don’t have to see the area you want to teleport to, and there’s no damage.
Summon greater demon – Drop this bad boy right behind the enemies you’re fighting and make sure your allies keep the enemies between you and the demon you summon. Even if it makes it’s Charisma saving throw against you, as long as another non-demon is in between you and it by Rules as Written it’ll go after the other thing first. Immediately order it to give you its true name when you summon it for disadvantage on the saving throw. Solid demon picks include barlgura, babau, and dybbuk. Barlgura are great for brawling scenarios. The other two picks are good for extra spells like dispel magic, fear, and dimension door. A dybbuk has dimension door at will, this is incredible for moving the party quickly.

Level 8 Warlock

Ability Score Improvement (Feat) – Inspiring Leader. This feat lends a surprising amount of durability to our party and we’ll use it either after every short/long rest or once another source of temporary hit points that was leftover runs out. The temporary hit points generated with Inspiring Leader is 12 per ally you can talk to. That number will steadily rise as we level up and cap out at 25. While it may seem anti-synergistic with Dark One’s Blessing, this is more for the rest of the party than you. Mid-combat you will still regularly be getting the boost from your subclass feature. A hidden benefit to this feat is that party members who are stubbornly resistant to taking a short rest are more likely to do so if you provide them a selfish benefit. If your DM is generous regarding magic items, such as using the DMG Loot Tables for enemy treasure hoards, picking up the War Caster feat would be the superior option here as it would allow you to use a rod of the pact keeper or other magic item like a staff/wand while wielding ashield at the same time. Talk to your DM or read the table and determine if this would work for you. In a low magic setting or in a game with a DM who does not like to hand out magic items, Inspiring Leader is the feat to take. If you do take War Caster, take Inspiring Leader at level 16 and delay Resilient (Con) to 19. Similarly, you may wish to skip Inspiring Leader completely in a party with a character that has a similar, superior effect, such as Twilight Sanctuary or Protector Cannon.
Spell changes: +sickening radiance, +dispel magic, -command.

Sickening radiance – Cast this spell on enemies behind cover to flush them out. Place this on enemies hunkered down in a room with one entrance and watch them trip over each other trying to get out. Overlapping this on an ally’s web, plant growth, or other source of movement reduction can win an encounter by default. The radius on this is huge so combining it with Repelling Blast is definitely going to net you some good results. Sickening radiance is one of the spells that uses the “enters” and “each turn” terminology (like spirit guardians), so forcing enemies into it will double the exhaustion. it will cover up an entire room, or most of it, so keep your placement in mind. 
Dispel magic – Like counterspell, using a slot on dispel magic won’t be fun, but we’re at the level where nasty spells like upcast spirit guardians or wall of stone are being thrown our way and getting rid of those spells is important. Cast it to solve any magic trap/ambush/spell problems and then rest up to get the slots back.

Level 9 Warlock

Eldritch Invocation – Agonizing Blast, Grasp of Hadar, Investment of the Chain Master, Repelling Blast, Voice of the Chain Master.
Grasp of Hadar – Adding Grasp of Hadar on one of your beams allows you another strong option for battlefield control and flexibility. Like Repelling Blast, combo this with an allied area of effect spell/effect and environmental hazards. 
Spell changes: +synaptic static, +banishment, -fireball.

Synaptic static – Friendship ended with fireball, now synaptic static is my best friend. It’s like fireball, but a better save and an extremely debilitating rider. It is also a much less frequently resisted damage type. These advantages provide far more value than 7 additional fire damage. This spell would be an auto-pick even if it required concentration. It does not.
Banishment – Banishment upcasts well and sometimes you just need a couple of enemies to go away for ten rounds and suddenly the encounter is far more manageable.

Level 9 Strategy

We’re using synaptic static instead of fireball for our fights. The other tools we have are situational but still very good options in the right setting, such as fighting extraplanar enemies and sending them away immediately with banishment. More than likely you still have more fights per short rest than you do spell slots so assess the battlefield before your turn and decide on either casting a spell or using your cantrips to augment your allies’ abilities and deal some damage at the same time.

Level 10 Warlock

Fiendish Resilience (Fiend feature) – Swapping out the damage resistance every day is nice. Adjust it as needed based on what environment you think you’ll find yourself in.
Spell changes: +fly, +mage hand, –darkness.

Fly – Most full casters are going to skip over fly because there are better third level picks, but since your class will auto-upcast and regains slots on a short rest, this can be extremely handy. Melee allies can participate in three dimensional combats, or you can use the spell for getting around obstacles in dungeons and exploration, or defeat melee-only enemies with ease (which somehow remain common even at high levels).
Mage hand – Utility cantrips are always nice and the ability to fiddle with things that may be trapped without having to be close enough to be affected by the trap is convenient.

Level 11 Warlock

Mystic Arcanum – 6th. A second set of spell slots to track. We’ll list our Mystic Arcanum choices each level as Spells Known, but remember you are completely restricted using these spells and slots. 
Spell changes: +mass suggestion, +scrying.

Mass suggestion – We can only cast a Mystic Arcanum spell once per day, and we cannot upcast it, so we have to make sure we have a spell that gives us a lot of bang for our buck. Mass suggestion allows us to defuse one encounter by giving a suggestion to up to twelve creatures that can understand you to save themselves and flee. It lasts 24 hours so anything you affect is guaranteed to go away for a very long time. The suggestion doesn’t have to just be “move far away”, but this would be a minimum expectation. Discuss this with the DM, but “reasonableness” here mostly just means to not do directly harmful things. “Knight giving horse to a beggar” is an example in the spell text for suggestion.
Scrying – Spying on enemies is good for advancing the plot, discovering secrets, and preparing the party for future battles, and you can recover the slot used for it on a short rest and we can do this several times on a day of downtime. The material component has a 1,000 gp cost but that should not be difficult to acquire at this time.

Level 11 Strategy

At level 11 we get a huge boost in power—three spell slots per short rest and three beams from eldritch blast—but our overall strategy is already largely set in stone. Cast synaptic static round one (when in an encounter that warrants casting a spell) or use one of your other combat spells if there’s a unique circumstance that makes it superior to your standard big gun. Subsequent turns are eldritch blast casts with three beams (and a lot of movement control options) or mind sliver to set up an allied spellcaster’s save or suck spell. Remember to have your familiar pelting things with its shortbow.

Level 12 Warlock

Eldritch Invocation – Agonizing Blast, Grasp of Hadar, Investment of the Chain Master, Lance of Lethargy, Repelling Blast, Voice of the Chain Master.
Lance of Lethargy – At this point you’re casting three beams with your eldritch blast. Combining this with Repelling Blast on one of them makes for some very nice control, especially on enemies in difficult terrain or in area of effect spells such as plant growth, sickening radiance, or spirit guardians.
Ability Score Improvement – +2 Cha. It’s time to max our Charisma, which will max our spell save DC and our spell attack rolls as well.

Level 13 Warlock

Mystic Arcanum – 7th. This has the same restrictions as the previous Mystic Arcanum.
Spell changes: +forcecage, +darkness.

Forcecage – This is one of the best 7th level spells in the game, it’s absolutely phenomenal control. Automatic pick. 

Level 13 Strategy

We’re picking darkness back up because we’re likely running into high level spellcasters and sight is required for some of some nastiest spells in the game. Casting this on ourselves allows us to negate many of their capabilities.

Level 14 Warlock

Hurl Through Hell (Fiend feature) – Hurl Through Hell is a pretty good feature. Note the damage isn’t anything to write home about but the enemy is thrown through a different plane until the end of your next turn and there’s no saving throw, which is great. At this point in your campaign you’ll likely be encountering some very powerful enemies like vampires, dragons, gith or drow leaders, liches, etc. Delete one of their turns when you hit them with an eldritch blast and give your party a round of set up or a round to clean up the mooks. Legendary Resistance can’t ignore this as there is no saving throw tied to it. Handy and reliable. 

Level 15 Warlock

Eldritch Invocation – Agonizing Blast, Devil’s Sight, Grasp of Hadar, Investment of the Chain Master, Lance of Lethargy, Repelling Blast, Visions of Distant Realms.
Visions of Distant Realms – Sometimes we need to do some scouting and either don’t have time to find our familiar if they died or we need them to scout something else. This is where arcane eye at will comes in handy.
Mystic Arcanum – Same as before, only 8th level now.
Spell changes: +demiplane, +arcane eye, +magic circle.

Demiplane – It’s like a bag of holding, but large enough for furniture, a house, or a dragon’s hoard. If you have a Bard, Cleric, or Wizard in the party they can use a high level spell slot on planar binding and then store whatever is bound in here.
Arcane eye – Via Visions of Distant Realms.
Magic circle – This is a very handy spell to use with summon greater demon and planar binding. We’ll pick it up now since we’re not the only class that can cast planar binding and can be difficult to keep a demon or something in place for the duration of planar binding without magic circle. Between this and planar binding, coordinate with your party to figure out who should take which spell for the least cost.

Level 16 Warlock

Ability Score Improvement (Feat) – Resilient (Con). Adding proficiency to concentration saves is the big draw for us, but other Constitution saves are quite common too, including most saves vs poison, paralysis, and effects that do necrotic or cold damage.

Level 17 Warlock

Mystic Arcanum – Finally we get our 9th level spell, beautiful.
Spell changes: +true polymorph, +planar binding.

True polymorph – Turning your party members into adult gold dragons (or any of the high challenge rating monsters you like) has a lot of upside and very little downside. It lasts until dispelled or until the form drops to 0 HP, but even casting this spell mid-combat is good. Also make your own army by casting this on rocks on the road in downtime.
Planar binding – Bind anything extraplanar and use it as additional bodies/fodder in combat. At this level you should be able to cover the cost pretty easily and this is great on short rests. Remember this can be used multiple times a day on a day of downtime. Because you can’t upcast this, another spellcaster may be the preferable character to cast it, but if no one else can cast it 5th level planar binding is better than no planar binding.

Level 17 Strategy

We are now shooting four beams with eldritch blast and we have four spell slots that recharge on a short rest. We have some interesting tech options with planar binding and magic circle but overall our strategy of using synaptic static or one of our Mystic Arcanum spells and then subsequently casting eldritch blast is still the same.

Level 18 Warlock

Eldritch Invocation – Agonizing Blast, Grasp of Hadar, Investment of the Chain Master, Lance of Lethargy, Repelling Blasts, Voice of the Chain Master, Visions of Distant Realms, Whispers of the Grave.
Whispers of the Grave – We have all of the invocations we need to round out our character. This final pick is mostly an additional method to gather information from everything we fight and kill. We’re shooting first and asking questions later, which works if our questions are geared towards finding our next targets to shoot.
Spell changes: +speak with dead.

Speak with dead – Via Whispers of the Grave.

Level 19 Warlock

Ability Score Improvement (Feat) – Lucky. This gives us a way to reroll failed saves, which might be important as we’re fighting demon lords, ancient dragons, and named liches/wizards that have great and terrible abilities.
Spell changes: +teleportation circle.

Teleportation circle – At this stage in the game you’ll want a reliable way to get around the world quickly and this provides an option that recharges on a short rest. Full casters might forgo this spell because they chose wall of force, wall of stone, animate objects, transmute rock, etc. but once again short rest slots come in handy with the utility options.

Level 20 Warlock

Eldritch Master – You did it, you reached level 20 and can now regain your spell slots when you don’t have time for a short rest, once per day. A somewhat underwhelming capstone but welcome nevertheless. You can now cast synaptic static eight times a day guaranteed, more if you take short rests.