Hakan is Eli's caretaker and the person who gets her blood for her. Based on the novel, Hakan appears to have a sexual and partly romantic relationship with Eli, but this is left for interpretation in the 2010 film version. Hakan dies after a failed attempt of blood retrieval get his seen (therefore he burns his face with acid) and he offers his blood to Eli in the hospital and shortly after falls out of the window and dies.
In the novel Hakan fails his attempt while stalks 2 young boys in a the pool public dressing room. He has an erection and ejaculates on one of the benches in his private changing room while watching them over the top of the door. This is evidence Hakan is in fact a pedophile in the novel version; along with his many desire and erotic attempts to touch and caress Eli.
Hakan's meets a tragic fate after burning himself with acid in the novel version, and becomes a vampire after offering his blood to Elias. He came back from the dead after falling from a third story window, kills the morgue attendant and then shambles to the suburbs to find Eli. He attempts to anally rape Eli but fails and is eventually smashed to a pulp with a shooting trophy by a neighbor boy who is accidentally locked in a fallout shelter with him.