The Dark Messiah

The Dark Messiah (aka Satan, Lucifer, Commander Of The Supernatural World) is the seemingly immortal demon of the mansion in Clock and is the primary antagonist.

Worshipping & Banishment
The Messiah is an obscure deity, born during the Big Bang. He was worshipped by the Sumerian’s and Mesopotamia around 500 BC associated with destruction and colonising the universe. A rival, one of Lucifer’s minions, opposed his goal and banished his from this plane. Satan is genderless, although thought to be a male during the events of Clock.

Reign of the Supernatural World
Since his banishment, he had remained in Hell before using scientific methods to create a portal between realms, thus managing to open a new dimension known as the Supernatural World. After centuries of using technology, he finally managed to get to Earth and attempt to colonise the world.

Iniquitous
During Albus’s sheltering in the castle, The Dark Messiah hunts him down, but is found in his inner sanctum. Eventually, he is banished from the castle as it explodes. He is returned to Hell, suddenly weakening.

During the Evangelists era, Satan continued to possess houses and people in order to kill everyone of Earth. He was eventually exiled back to Hell, but managed to create a portal to reality and forge a new portal to the Supernatural World to keep victims in.

Clock
The Dark Messiah’s mission is to kill everyone that rents the mansion. During the time Steve and his father were there, he locked them in the supernatural world. He possesses Steve’s father in order to keep secret of his personality. However, towards the end, he is weakened one last time before the Supernatural World collapses on itself and the Dark Messiah withers away inside the Stag: the Symbol of the Evangelists.

Afterwards, he is no longer mentioned likely because he finally was eradicated from the universe forever.

Personality
He is seen as a sadistic, sinister and demonic entity. The Messiah has a hatred for Heaven and religions that are against him. His goal of destroying the universe had become zealous until his ultimate fate when he is weakened one last time before decaying into nothingness.