Atilla is a character featured in Dying Light: The Following.
Prior to Outbreak
Very little is known about Atilla's past, other than the fact he is an ethnographer (likely specializing in cultural religious practices and events given his later tasks.) Atilla, as it would seem, came to the Harran countryside to use his skillset with local artifacts related to the Children of the Sun. He came into contact with "The Colonel" and his wife, Jasmine. It is implied that, at some point, the three kindled and shared a friendship. Atilla is also suffering from, according to the faceless, a form of cancer that "is eating at his brain."
Atilla agreed, at the request of the Colonel, to remain behind when the outbreak started to spread to the countryside, likely so he could return to the military and organize an attempt at containment or triage for those affected by the virus. Atilla stayed with Jasmine until, at some point later, the Colonel returned to evacuate her. According to Atilla's letter (and last words to Crane), at some point during this rescue attempt, the Colonel was bitten and turned. The Colonel also gave Atilla something to give to Jasmine (The Mother), but only assuming that she had managed to not allow the events of the outbreak to cloud her judgement or drive her to complete insanity. This was likely the 8-digit pin code which would activate the nuclear weapon in the dam. Unfortunately, Jasmine left Atilla's company sometime after the Colonel's death, and Atilla never saw her again.
Events of Dying Light
Crane is requested, by the Faceless, to find Atilla and assist him with his research on their prophecy. Crane finds him drinking heavily and without any power. After restoring the power, Atilla sends him out to research (his cancer restricts him from going into the field himself, coupled with the horde of undead outside the home). Crane locates a number a monoliths detailing portions of the prophecy, and finds a red mask which he later brings to Atilla. Crane leaves Atilla and returns a short time later. He finds his office empty and with a note on it, detailing his coming to Harran, the outbreak, the requests made of him by the Colonel, and the depression he suffers from having been left alone by the Mother. Atilla gives Crane the 8-digit code likely left to him by the Colonel in the letter. Crane searches the house, only to find that Atilla has slit his own throat while wearing the red mask to try and manifest the God of the Sun in himself, in accordance with his interpretation of the prophecy. Crane takes the mask and leaves.