I guess with enough observation, you could make an educated guess. Okay.

[ Nico lifts his arm with the affected patch of skin, no hesitation in the act. He'd rather this one first if it will fix the one on his chest too. ]

We've been turned into squids that can die and come back, our blood type entirely changed from the start. That isn't exactly ordinary.

[ A thoughtful hum. ] Then maybe a permanent change also means a change in their original powers. If I suddenly start having better control over my elemental abilities, then maybe we could check my bloodtype.