One (1) is an Algebralien and the main antagonist of Battle for Dream Island: The Power of Two. She made her first canon appearance in the stinger of "Outbreak At Stake" where she emerges from the damaged Moon, which she was trapped in by Four. 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.