Devil Bringer

Because of your demon heritage and your lack of child support your hand has become a strange demonic hand 

You can pull people towards you and toss people around in  brutal takedowns 

You can later transform into a powerful devil form 

(Nero from dmc)

Level 3: Devil Bringer

Your hand has transformed into a demonic hand which can pull enemies to you
you can pull a thing or an enemy towards you
if you pull an enemy it has to roll a dex save of 14 or get pulled in an 30ft area of your choice
has a range of 30ft

the hand will also glow and sting in the presence of Fey, Demonic or Celestial creatures 

Level 3: Chaotic Burst

As a non action you can take a -5 to hit penalty for a +10 damage buff if hits
at 7th level the buff turns to a +15 and a -7 penalty
and finally +25 and -12 at 15th level

this can be done 3 times 

Level 7: Buster

When you roll a critical hit you can do a powerful attack to an enemy
add 2d10 force damage turning to 4d10 at 15th level
additionally you can hold your action to do this for your next action

this is done as a bonus action 

Level 10: Devil Trigger

As a bonus action you can transform into a devilish form increasing your power and healing you
your attacks deal 2d10 extra damage and healing you 1d12 hp
lasts 2 rounds turning to 4 rounds at 18th level
this has 2 uses but when you deal a critical hit buster you can do devil trigger again

Level 15: Devil Wings

You can summon wings that allow you to fly short distances
you get a flying speed of 15ft
you can summon these wings as an non action  

Level 15: Devil Hold

When you deal a buster you can hold an enemy for 2 rounds
when it's the enemy's turn they have to roll a dex save of 17 to get out
this has 3 uses

Level 18: Devil Sword Slash

You can summon a phantom blade that slashes your enemies into nothing
deals 6d12 force damage
this has 3 uses