Mephisto

The Cat is a prat.
Anyway.
So, Mephisto is the ice primordial, a result of the energies from Fire and Ice primordial energy. Asmodeus froze him into place during their fight for the Titans' bodies.

He is the eighth of the Nine, and the longer you stay in his realm, the more likely you are to hit an entropic point of no return and freeze in place.