Friendship is magic!
Warlocks are one of the most customizable Dungeons & Dragons classes, with a patron at level 1 and the actual subclass (the all-important Pact) at level 3. While patron choice has a huge impact on the flavor of your warlock, the mechanical meat of this layered and rewarding class lies in your choice of Pact.
I’ve been using this Pact of the Chain build in my own game, and I can thoroughly recommend it! The Pacts all have their own playstyles to recommend them, and the Pact of the Chain might seem underwhelming at first glance, as wizards already get the find familiar spell. However, the warlock familiar is an entirely different animal. Quite literally.
The Pact of the Chain allows the warlock to cast the find familiar spell as any run-of-the-mill wizard can, but while most find familiar spells can only summon a fairly ordinary creature, albeit a magical version, Pact of the Chain warlocks can choose their familiar from imps, pseudodragons, quasits, and sprites instead. My personal favorite is the psuedodragon, for reasons I’ll come to soon.
All familiars have their own initiative and can take a move and an action (such as the Help action to give the caster an advantage on their attacks against that target). Pact of the Chain familiars, unlike other familiars, can be commanded to attack by their pacted warlock, but the warlock must give up their own action to give their familiar an attack on the warlock’s initiative. Luckily, the Investment of the Chain Master invocation from Tasha’s Cauldron of Everything, allows you to use your bonus action to attack with your familiar.
The other key part of this build is that the Investment of the Chain Master means that whenever your familiar forces an enemy to make a saving throw, it uses your spell save DC instead of its usual saving throw. This is where the pseudodragon shines compared to the other familiars: its sting attack has very limited damage but forces its victim to make a Constitution saving throw using the warlock’s spell save DC for the saving throw. If the target fails the saving throw, they become poisoned for an hour, which imposes a disadvantage on all attack rolls and ability checks, and if they fail by 5 or more, they immediately fall unconscious.
What this means in practice is that the familiar can move within 5 feet of an enemy on its turn and use the help action to give the warlock an advantage on their next attack against the target. The warlock can use their bonus action to command the pseudodragon to attack the target. The warlock then has their own standard action free to make an attack with an advantage on the target from the help action or cast another spell.
This has some potential weaknesses: if the pseudodragon gets taken out (which did happen to my warlock’s familiar during an early adventure), your combat ability is somewhat hampered, though you still always have your spells. Luckily, Pact of the Chain warlocks can use their reaction to give their familiar resistance to the damage it just took. Look after your familiar and it will look after you!
You can also use any familiar to deliver touch-range spell attacks on your turn with your attack modifier rather than theirs, so you may wish to consider taking the Magic Initiate feat for the Sorcerer and gain the Shocking Grasp cantrip, as Sorcerers use Charisma for their spell attacks.
Warlock Pact of the Chain Build
Attributes: High Charisma (vital for any Warlock — put your highest attribute score in Charisma and ideally take a species bonus to Charisma). Other attributes are very much up to you.
Patron: Patrons that provide access to spell attacks such as Scorching Ray from the Fiend or the Genie, or the Tentacle of the Deep from the Fathomless, or touch spells such as Cure Wounds from the Celestial, have slightly better synergy with this build.
Invocations (level 2): Agonizing Blast and another invocation that you will replace at level 3 with Investment of the Chain Master.
Pact (level 3): Pact of the Chain with the pseudodragon.
Spells: Eldritch Blast is the real favorite here, as it is a ranged spell attack that you can use in conjunction with your familiar’s help action. For your other cantrip, Mind Sliver subtracts 1d4 from the target’s next saving throw, making them more vulnerable to your pseudodragon’s poison.
