The Great Trickster

Trickster Warlocks are those who have a patron who enjoys trickery. Often these patrons are fey but they can also be demons as well. Trickster Warlocks employs methods that often trick or confound their enemies, gaining an advantage from deception and disruption. More rarely Sorcerer-Kings make Trickster Warlocks out of a Templar, usually to make them a spy.

Spellswipe

   Starting at 1st level, as a reaction when you see a creature within 60 feet of you cast a spell, you can expend a spell slot to try to steal the spell. If the spell slot you expended was equal to or higher than the spell’s level, its spell fails and instead produces a momentary harmless sensory effect of your choosing.
In addition, you can add the spell to your spell vault.
   You can have a number of spells in your spell vault equal to your Charisma modifier (minimum 1). If adding a new spell to your spell vault would cause you to exceed this maximum, choose one spell from your spell vault to lose. All spells in your spell vault count as warlock spells you know, and don’t count against the number of warlock spells you know.
   As a final benefit of this feature, you can cast a spell from your spell vault without expending a spell slot. When you do, you lose the spell from your spell vault immediately after you cast it. Once you cast a spell this way, you must finish a long rest before you can do so again.

Thieves Cant

   Your connection to an entity of mischief personified allows you to understand thieves cant, a secret mix of dialect, jargon, and code that allows you to hide messages in seemingly normal conversation. Only another creature that knows thieves’ cant understands such messages. It takes four times longer to convey such a message than it does to speak the same idea plainly. Your connection to an entity of mischief personified allows you to understand thieves cant, a secret mix of dialect, jargon, and code that allows you to hide messages in seemingly normal conversation. Only another creature that knows thieves’ cant understands such messages. It takes four times longer to convey such a message than it does to speak the same idea plainly.
   In addition, you understand a set of secret signs and symbols used to convey short, simple messages, such as whether an area is dangerous or the territory of a thieves’ guild, whether loot is nearby, or whether the people in an area are easy marks or will provide a safe house for thieves on the run

Trick is Trade

Also starting at 1st level, you can use a bonus action on your turn to magically conjure a disguise kit, forgery kit, or thieves’ tools. You add your proficiency bonus to ability checks that use the conjured tool kit if you aren’t already proficient with it. This tool kit remains until you use this feature again to conjure another tool kit.

Steal Fortune

Starting at 6th level, when a creature you can see within 30 feet makes an ability check, attack roll, or saving throw, you can use your reaction to give that roll disadvantage. When you do, one ability check, attack roll, or saving throw of your choice that you make within the next minute gains advantage. Once you use this trait, you can’t use it again until you finish a short or
long rest.

Skeleton Key

Starting at 10th level, you have advantage on saving throws against being restrained and ability checks made to escape a grapple. Additionally, you can cast the knock spell at will, without expending a spell slot.

Two Steps Ahead

Starting at 14th level, you can’t be surprised. When you roll for initiative, you can use your reaction to position yourself for an ambush. When you do, you gain a +20 bonus to your initiative roll, you have truesight out to a range of 120 feet and turn invisible until the end of your next turn, and can immediately teleport to any unoccupied space within 120 feet. Once you use this feature, you must finish a long rest before you can use it again.