about Mikoto Itoshiki
The third son of the Itoshiki family, with an uncanny resemblance to Nozomu. He is a doctor in his private "Itoshiki Clinic". When his name is written horizontally, it resembles zetsumei (絶命, "death"), which explains why his hospital is rarely visited by town's residents. He has a tendency of losing control of himself whenever his name is brought up, especially if he is referred as "Zetsumei-sensei" ("Dr. Death"), which explains the title of this fanlisting.
Note: His seiyuu is Hiroshi Kamiya who also made the role of Mikoto's brother, Nozomu.
what's a fanlisting?
It's a list of people who like squeeing at a paticular thing or topic, could be also a character like in this case. The idea is that the bigger the list, the more loved that topic or subject is. Also it's good to meet people who like the same things you do.