Three (The Ark)

Three was a Monoid who lived on the Ark in the 57th segment of time, 700 years into the ship's voyage.

Biography
Upon the vessel's arrival at Refusis II, Three discussed the issue of what should be done with the Ark's humans with One. One informed Three that he had hidden a fission bomb on board the ship, that would be used to kill the humans once the Monoids were settled on Refusis. Three also warned One that he believed that Four was planning a mutiny. Three was correct, and was killed in the process of Four's attempted mutiny. (DW: The Ark)

Behind the scenes

 * Of the Monoid actors (Edmund Coulter, Frank George, Ralph Carrigan, John Caesar), it is never made clear who played which Monoid.