He is a skilled assassin and spy and comes to St. Louis, in The Harlequin, and gets a job as security at the Circus of the Damned. His purpose was to keep an eye on the rogue Harlequin. Jake helps Anita defeat them and before he leaves town, gives her a medallion to protect her from the Mother of All Darkness.
He returns to St. Louis, in Bullet, with a small group of yellow tigers, and asks Anita to offer them protection. It is revealed that he and his master have been hidding and protecting yellow weretigers for the last two thousand years, until the tigers would be needed to stop Marmee Noir. Jake and his master are considered family by the yellow tigers and Jake is very attached to them. He remains in St. Louis and works as security at the Circus, and also helps Anita hunt down Padma and free him from Marmee Noir's control.