Assailant
From CreatureWiki
For a long time The Assailant carried out all of Mortismere's devious plans. Nobody knew who or what the Assailant was because it's head was covered with a black mask- we did know that the Assailant was commander of the Mortismere's Darkside elites.
While using it's intense evil powers, the Assailant successfully attacked Gojinn along with commanding the darkside elites. The climatic ending of the Assailant happened on the CW match: Torment Compartment? where Assailant's mask was removed revieling an aged Alexander Arcane?.
We later realize that Assailant was Mortismere's 'bridge' of transport into our realm. After Mortismere was done with partially possessing Alexander Arcane- all supernatural powers from Alex disappeared.