The Prisoner

You have forged a pact with a prisoner from Carceri, the prison plane. This Prisoner may be making a pact to continue their legacy on the Material Plane since they are now bound in Carceri for eternity, or are making pacts to find a willing participant to free them from their chains and let them loose once again. Whatever reason the pact is made, The Prisoners goals are ultimately the sole purpose of it, though whether you realised this when you first discovered the Prisoners legacy and made contact with them does not matter. 

Expanded Spell List

The Prisoner lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Prisoner Expanded Spells

Spell Level	Spells
1st	alarm, command
2nd	blindness/deafness, detect thoughts
3rd	Leomund's tiny hut, nondetection
4th	Leomund's secret chest, wall of fire
5th	planar binding, passwall

Tool Proficiency

When you choose this subclass at 1st level you become proficient in Thieves Tools.

Escapist

Starting at 1st level, if you become grappled, restrained or otherwise unable to move, as a bonus action, you can teleport to an unoccupied space that you can see within 10ft to escape. You can use this ability a number of times equal to your proficiency bonus.

Chains from Below

Starting at 6th level, you can create spectral chains to ensnare enemies. You can cast hold person at will without spending any material components or spell slots. 

Once you use this feature, you can’t use it again until you finish a long rest.

Lockpicker

Starting at 10th level, as an action you can unlock locked doors as long as the lock is nonmagical or the magic binding the door closed is of 4th level or lower. You can identify whether a magically locked door is unlockable with a successful Intelligence (Arcana) check with a DC of 15 minus your Charisma modifier.

Demiplanar Dungeon

Starting at 14th level, as an action, you can use choose one creature you can see within 30ft to be sent to and imprisoned in Carceri. At the end of your next turn, the target returns to the space it previously occupied, or the nearest unoccupied space. The target takes 8d10 psychic damage and is grappled by illusory chains. Once you use this feature you can't use it again until you finish a long rest.