Dark Leviathan

A mysterious being that descended without warning, cloaked in an ominous aura of water. It bears a striking resemblance to the esper Leviathan and possesses the power to manipulate water at will, unleashing torrents that destroy its enemies. Although it is every bit as powerful as an esper, it is ultimately an imposter, for where a real esper can be mindful, this creature will wreak havoc based on nothing more than an impulse. All the same, it would take no small amount of power to bring down something so ferocious.