Talius

Talius is a mutant who resides in the basement of the library of the Followers of the Apocalypse.

Background
Talius was a vault dweller from Vault 13, sent out by the Overseer to find the Water Chip. Together with Ed, this means there are two confirmed Vault Dwellers from Vault 13 who went out before the Vault Dweller. Supplied with a shotgun and some shells, Talius searched unsuccessfully for the Water Chip for some time before hearing of Necropolis's water pump. Presumably hoping that the pump's source was, in fact, a functioning Water Chip, he traveled to the city not having known of its newly garrisoned detachment of super mutants.

With the help of the ghoul leader Set, he was able to kill some of the mutants before being knocked unconscious by Nightkin, and promptly taken to the Mariposa Military Base. He was dipped in the Vats, which led to a rare transformation into a ghoul-like mutant similar to Harold, as opposed to the typical super mutant. He was rescued under ambiguous circumstances by the Followers of the Apocalypse, in his words, "from the full effects of the transformation into a heinous beast". He joined as a full-fledged member shortly afterwards.

Other interactions
Talius will help the player along by giving him a flamer if he promises to battle the mutants in Necropolis or after he killed them already, or Mentats if the PC has less than 4 Intelligence.

Talius is also a part of the Find Children spy in the Followers, a quest he'll give you if you accuse him of being the spy, though this quest is broken and cannot be finished.

Appearances
Talius appears only in the first Fallout.