Santiago is a tainted operative of the demon Malphas who has been present in New Gauntlet City since its founding. Santiago has a powerful demon form he uses to fight other supernatural entities at Malphas;s bidding, but also feels like a mere plaything for his demon patron. Santiago is the main character of the mature-readers comic series "Knick Knack."
In the Narcosis Comics series "Ex Libris," sequel to "Coven Prime," Santiago investigates a number of shadowy rumors in the city, including the stolen volumes from the magical library, the unburied dead rising en masse, vampire impresario Vincent Brama running feral in the sewers, and the Fury possessing DA Mia Burke. Santiago works more or less willingly with Anna Kogotov, Silas LeBeau, and Cam. Santiago was last seen sneaking into the DA's office just in time to disrupt an occult ritual. Santiago helps free the DA from the Fury and then spends the night with her.