[Shujin]

Ki Awoken gives an absolutely massive stat bonus, as stated in the OP, I'd like to see it be less about stat padding and more about providing a more useful power cost, I would like to also suggest exploring a stacking Worn Out debuff as a drawback as well, instead of or accompanying an associated HP% Cost.

That thought crossed my mind serval times, with serval high power buffs such as potions. Though Ki awoken certainly is the worst offender of over self destruction in a similar vein of painproof.

Ki awoken is very gimmickly as it stands, the by round increasing HP cost for what it actually does is not really feeling good. I'd probably remove the by round increasing HP cost effect (or drastically reduce it), and instead add some sort of penalty to stats/worn out effect once its turned off based on how many rounds it was active.
While the stat padding is "nice",  it certainly doesn't outweight the costs and is not really interesting.
I could also see reduced damage during the active time but once off you receive more damage for a couple of turns. Stuff like that would be probably more interesting than the Climbing HP costs.