Soul Fighter

You have been treated weak for your entire life even though you've trained your life to fight with your fist so after so long you've had enough and decided to use the souls of those who mistreated you and those you defeated to show everyone why you aren't weak.

Soul Seeping art

You take the souls of those you defeat in battle to make you stronger.

When you defeat an opponent make a charisma check against the opponents wis saving throw; if you succeed then increase a stat by 1: at later levels you can split the stat increases between stats 

but you can only increase a single stat using this ability by 2x your level if you try to go higher the dm at any time can make you make a wis saving throw dc 10 + the stat that's over the limit; if you fail half that stat. If you somehow succeed you keep the stat but can't grow it until your at the right level. 

Shadow gauntlet

You have the ability to shape your shadows into gauntlets to make your strikes stronger and or faster.

You can decrease a stat to either increase your to hit bonus and or damage bonus.

At the end of the turn return everything to normal but make a wis saving throw equal to 10 + the total count of stats used;

If you fail you gain 1 level of exhaustion for every 5 stats used 

Shadow summoning

You have the ability to lower a stat by the cr rating of one creature that you've consumed the soul of and summon a shadow version to fight for you.

You have the ability to recall the shadow to get back half of the stats used to summon it.

Shadow reinforcement

You gain the ability to straighten your defense with the shadows you've gathered.

You can lower a stat to 1 and increase your AC with those points.

 

At the end of combat make a dc 22 wisdom saving throw if failed you lose half of the points used in this ability otherwise the stat and AC go back to normal.