He is first introduce in the episode  entitled "Intruders". He plans to facillitate in the sale of the Occido Lumen. Then Abraham Setrakian and Eldritch Palmer finds out who has the book. They started bidding for it. And Thomas Eichhorst started bidding for the book too. Abraham Setrakian and Vasiliy Fet did not have the funds to bid so they decided to rob the cardinal.  Thomas Eichhorst arrives at the church, he brakes and enters the cardinal's room. Cardinal Mcnamara asks him vociferously to get out of his church while using his phone to dial 911. Thomas Eichhorst tossed the phone into a delicate glass cabinet which was shattered in the process . By the time Abraham Setrakian and Vasiliy Fet got to the church, they were to late, the Cardinal was lying on the ground, mortally wounded and unable to speak. Thomas Eichhorst escaped when Vasiliy Fet throw a light bomb in the room. Abraham Setrakian takes out his sword and puts him out of his misery before he turns.