One (1) is an Algebralien and a major antagonist in the Battle for Dream Island series, serving as the main antagonist of the fifth season, Battle for Dream Island: The Power of Two, as well as the main protagonist of the season's 20th episode "Alone".

One made her first appearance in the show in the stinger of "Outbreak At Stake", where she emerges from the damaged Moon, which she was trapped in after being ostracized by Four and the other Algebraliens after she killed Three in 2009. Prior to that, she first debuted in "X Finds Out His Value" and was shown as a recommended character in "The Tweested Temple".

She had her first major role in "What's Up Bell's String?", where she is seen kidnapping characters and making deals with them. Her main motivation becomes clear in "Alone", being to retrieve the powers from all of the other Algebraliens to enact revenge on them and in order to undo the effects of Three's poor recovery.

Last bot before I go work on my list of bots in my bio.