For as long as there's been a Vatican
the Church has hunted Simeon Magus.
He is tired of running...
Simeon Magus has been alive... undead nearly two millennia.
He has watched the undead go from myth to adored celebrity and he exists,
hiding from a determined and lethal group of hunters who do not listen to
reason and won't stop until he's destroyed.
Eternity gets lonely when you've seen your friends and those you love destroyed.
You end up not being able to trust, or not wanting to feel because behind every smile or kind word could lead to those who are hunting you just because you exist.
Simeon wants to live, wants to connect with someone again but he's afraid.
He is ever wary of the only other constant he's known in his millennia long existence: The Jesuits.
Beneath the veneer of charity and compassion their order there exists a secret army of killers whose sole task is the total annihilation of any supernatural being their masters order them to destroy.
The Templars never went away they were re-purposed and renamed the Vatican Slayers.