User is a fox demon

Pros:
-user is tied to targets and can influence them quickly
-user can shift to fox or demon form
-user is insanely smart and stealthy
-user can blend demon and fox form
-user can change form freely
-user can adapt to quirk of target
-user can control target when in animal form

Cons:
-user is in pain away from target
-user will be more comfortable in animal form
-user will show unwanted emotions of target
-user can't hold blended form for long
-user will always change form when bored
-user doesn't know control over target's quirk quickly
-user can only control target when in animal form
-user will be out of control when away from target

Weakness: no target
User is "mildly bored" without a target