Six Paths; Human
This feels...super unfun, unless you get off on making other people miserable. The fun part is getting a neat EXP boost, but taking away someone else's until they earn it back is a little counter-productive for the game. When we re-balanced the EXP table there were still gripes about forward progress despite the EXP boost and the fact that everyone else was in the same boat. Since you don't actually lose levels, it's not an ability that would inspire 'loss' or 'feelings of weakness' but rather frustration and getting stuck. It's not that the ability is too strong, I just feel like there are better options out there.
I would recommend taking it more in the direction of EXP gain, or perhaps stat losses become permanent in the battle, but are gained back after the battle (that way you are actually making the character weaker).
Six Paths; Preta
What are the parameters of absorbing chakra? Is this something going to be listed out in the technique? If so, that's fine.