Thread:ShonenChicoBoy/@comment-25456115-20150126135756/@comment-1493741-20150126161325

I think he needs more than just high school, man. This is the guy that thinks seeing the future makes you invincible, but only if you have three eyes on one eyeball instead of four.

The way I see it, the first strike injects the venom in a "passive" state. This allows it to circulate faster than a normal venom when it enters the blood stream. Acting as the foundation of the ability, and the set up for the second strike. Within minutes, the body is filled with the venom, but its largely benign in that state and in such a way as to not cause the body of the victim to go ballistic and try to get rid of it. The second strike is a trigger, which "awakens" the poison and then ta-da dead person. Then again, its also unremovable unless Sui-Feng wills it... unless someone has a greater willpower than she does.

Looking at the references, its only in the anime (Ep. 100), so, not Kubo in this case, but the show writers? Assuming Kubo didn't give them that detail (I don't know how much he's allowed to consult on the anime; if at all).