Doctor Nebun was a vedalken and a member of the Simic Combine. His base of operations was located in Utvara. A skilled viromancer and cytoplastician, Nebun was responsible for creating potent viruses that destroyed thousands. Nebun devoted his time to studying effects of the Utvaran kuga plague on its inhabitants, utilizing a huge laboratory.
After Teysa Karlov's arrival in Utvara, the Orzhov advokist confronted Nebun. She asked him for help against her narcolepsy spells and also persuaded him to hand her the already developed curative serum for the kuga plague, enabling the purification of Utvara from the epidemic. In addition, he provided Teysa's strike force with his virusoid golems for their attack on the Cauldron.
Later, Nebun did his best to help the citizens of Utvara wounded during the rampage of the nephilim.