The demon form of the demon kings, this was something that the Champions didn't even know too much about, but it was actually one's true form that each demon king had. As for the reason why they didn't just stay in that form all the time, it was due to the red energy in the air.
This was an order, and was forbidden, by Immortui himself. The full demon form would attract the red mist energy from all over, and he needed that to do its work, to do its thing, so the demons staying in their demon form for long periods of time would cause great problems for him.
Immediately after transforming, and now in front of the others, Bisha threw out his fist. He wasn't within range of the others, but the marking on his chest started to light up, and the red energy had gathered on top of his fist.
