As far as I'm aware. there are yet to be any gems to match the Enchanter's description.
So some effect suggestions ...
Cantrips- Turn off auto-attack and / or auto-shoot.
- Your opponent's next critical hit will target themselves.
- Gain the effects of all of your opponent's auras currently in play until the next time you take non-magical damage.
OTCs / Recasts- Turn off auto-attack and / or auto-shoot. Disable for ? seconds.
- Force target enemy's attacks to target one of their allies.
- All DoT effects on you are transferred to the target opponent.
- All DoT effects on you will instead heal you for the remainder of their duration. - Starting at 50% of the remaining damage, working up to 200% ?
Auras- The next status gem cast on you will be rebounded to the caster.
- The next (status/DoT/any?) gem cast on you will replace this aura in the spell slot. If replaced by another of your gems, the gem will not enter into your gem pouch.
- The next DoT effect cast on you becomes a damage shield equal to the total damage, lasting for the duration.