The Stolen Secret

You know the truth that most of the common folk do not: that there are other worlds than this one.

The beings that are not of this world have always intrigued you and you have studied the various ways in which mortals have entered into deals and shared power with these beings. But, you have never been much of a follower. You have devised methods and magics for stealing power from the outer realms. Perhaps you have studied on your own or perhaps you learned your techniques as part of an organization headed by a certain tricky tiefling. 

Either way, you have taken a path towards power that gives you a freedom and latitude that no other Warlock enjoys. However, there is always a cost. Stealing such power will make you many enemies from around the multiverse. Some of which may be very powerful indeed.

Arcane Trickery

Starting at 1st level, whenever a creature you can see within 90 feet casts a spell, you can use your reaction to learn that spell. The spell is added to your list of prepared spells and it counts as a warlock spell for you. You may cast it using a warlock spell slot (as long as you have an available spell slot of the appropriate level).
If the spell you attempt to learn is of a higher level than the spell slots you have, then you fail to learn that spell.
You can only have learned one spell at a time using this feature. If you learn a new spell, you lose the one you had previously learned.

Expanded Spell List

You have stolen the knowledge to cast the following spells. You can choose from an expanded list of spells when you learn a warlock spell. 

 

Spell Level Spells

1st	command, detect evil and good
2nd	locate object, zone of truth
3rd	sending, blink
4th	private sanctum, locate creature
5th	planar binding, conjure elemental

 

 

True Name Knowledge

Starting at 6th level, you have the power to impose your will over otherworldly creatures. As an action, choose a celestial, elemental, fey or fiend that can see and hear you and is aware of your presence. It must make a Wisdom saving throw against your spell save DC, and does so with advantage if you or your companions are fighting it. If it succeeds on the saving throw, it knows that you attempted to charm it and it is immune to this feature for 24 hours. If it fails the saving throw, it is Charmed by you for 24 hours. When this effect ends, the creature knows it was Charmed by you.

Eldritch Power

At 10th level, on your turn you may choose a celestial, elemental, fey, or fiend that is charmed by you or is currently obeying your commands. You gain one feature or action that creature has of the DM’s choice. You have this feature or action until you finish a long rest, or for 24 hours, whichever comes first.

Any statistics associated with the action or feature, such as attack rolls, saving throws or damage rolls use the original creature’s statistics and not your own. 

If the action is a weapon attack, a magical copy of the weapon appears in your hand for the duration.

You must finish a short or long rest before you can use this feature again.

Delver of Secrets

Starting at 14th level, you can wring secrets out of any creature you see before you. As an action, choose a creature that you can see within 60 feet of you. It must make a Charisma saving throw against your warlock spell save DC. On a failed save, the creature is charmed and incapacitated for one minute. At the beginning of each of that creature's turns while it is charmed in this way, you may ask one question. You may ask this question telepathically or verbally, but either way the question must be one which you can speak within six seconds. The creature responds telepathically and it must give a truthful reply to your question. At the end of each of its turns, the creature makes another Charisma saving throw. On a success, the effect ends on the target.

You must finish a short or long rest before you can use this feature again.