Hebi is a majin the takes a shape of any kinds of snakes 

power scale: high 6-A multi-continental

Hebi gives the host the power to summon any kinds of snakes and change there size as well. But the scary part of this is that it can get to the point that the host can change the aspect of the snakes to summon multiple of jormungandr and apophis tho they are less powerful then the original. But in order to summon them the host needs to fully understand both them.