The cat is the real devil. The one going around posessing people is a stand-in
Jericho is Jesus
Well, both of them have the same initials, tempted by the Devil, and in the end, died for everyone in the world. The baby Satan wanted to put in Christine wasn't the Antichrist per se...
But a Perfect Vessel à la Supernatural or Ghost Rider: Spirit of Vengeance, only a child of himself would be able to contain and use his full range of power.