Agent of Order

Agent of Order
Feat
Prerequisite: Level 4

You can channel cosmic forces of order to gain these benefits:
- Once per turn, when you damage a creature you can see within 60 feet of yourself, you can deal an extra 1d8 force damage to the target, and it must make a Wisdom saving throw (DC equal to 8 + your proficiency bonus + the modifier of the spellcasting ability you chose for the Scion of the Outer Planes feat) as spectral bindings try to ensnare it. On a successful save, the target escapes. On a failed save, the target has the restrained condition until the start of your next turn. These bindings manifest as chains or some other symbol of stasis. You can use this benefit a number of times equal to your proficiency bonus, and you regain all expended uses when you finish a long rest.

Source: Sigil and the Outlands (SatO), page 10