[quote=@Lekkuen]
[@Dead Cruiser]

Give me a ballpark of where their physical abilities actually lie. same with how strong Oni's tk is.  And how exactly the soul consuming works, like I take it they can't just casually suck up the soul of anyone they manage to bite instantly? 
[/quote]

Alright, this is kind of how I picture it.

Oni
Baseline strength/speed: Same level as an olympic athlete, if he gives only a moderate effort
Max strength/speed: Can swing around a cement roller like a baseball bat, and outrun a crotch-rocket motorcycle (sprinting)

Akuma
Baseline strength/speed: Like Bruce Lee, only smaller.
Max strength/speed: With maximum effort, she can make a small-scale earthquake. Sprinting, she can outrun a bullet.

I'm guessing you meant Akuma's telekinesis, since Oni has none. It's actually her pretty much ultimate ability, only available if she is restored to her true form. Which spells bad things for a lot of different reasons. But it's strong enough to be lethal; she could basically induce explosions just by looking at something.

The soul-devouring works very similarly to regular blood-sucking. It'll kill you just as fast, which means it can only be used in combat as a finishing move. It basically eats the "spirit" of a person/creature, and the memories and knowledge that come with it. It is possible to recover from this, just as you can recover from bloodloss, and they do need to actually bite you to do this. The major advantages are that it allows them to "eat" incorporeal entities such as ghosts, or things that are possessing other creatures.