From the ability video.

The dragon he shoots up, doesn't cost any botd time to use. However, its only purpose seems to be building to allow to go into red blood of the dragon. Looks like you need to do twice, followed by a GK to activate red.
GK no longer consumes a bunch of time off it, but instead adds a bit and takes you into red form at the same time.
Can use both 4th combos back to back.
So the question is.. what skill consumes our blood of the dragon? Nothing ate it as GK currently does?