Malak are born from the pure, untainted mana. That's what we call the life energy of our world. Some have appearances of animals too, not just human.

[ Surprisingly, she might be one of the few who's realized he's not exactly a ghost. Although, a spirit born of a death isn't entirely incorrect. There were some special cases, such as himself... ]

But in some very rare cases, malak are reincarnated humans.