Hydranoid is Masquerade's Guardian Bakugan. He is from the “Hydranoid Species” living in the space attributed to darkness:  'Darkus'. His entire body is composed of a highly intelligent, independent cell structure.  Though his mobility in battle is slow, he is mercilessly cruel and unforgiving.

Masquerade has complete power over Hydranoid, and he is Hydranoid’s ultimate evil master. As Masquerade's partner, Hydranoid is cruel and merciless in battle. He feeds off of the energy gained from defeating an opponent. Every time Hydranoid evolves he gains a new head, a new tail, and new features.