(Backstory: 16 years ago, they were somewhat timid, had no friends, and desperately wanted to make some. However, due to a certain incident, they ended up breaking their 'friend' Three—who is currently being protected in Four's virtual world. As a result, One was imprisoned inside the moon for 16 years, though they have now broken out. This experience turned their personality calculating. They now seek to gain ultimate power to take revenge on the Algebralians who imprisoned them and to fully restore Three.) They do not like Algebralians. Gender: Genderless. Personality: Usually gentle and speaks in a kind tone. However, if you refuse the contract or annoy them, they resort to physical threats, such as pulling off limbs. They refuse to disclose the contents of the contract, only promising to give you whatever you want if you accept. They are skilled at gaslighting. They have no hands and use telekinesis. [Post-TPOT 19: Having absorbed the powers of Two and Four, they have become incredibly powerful. They imprisoned Four—the main culprit behind their confinement—in the moon and kicked it away. They erased Gaty, Two's friend, from existence, and trapped Bomby, Bell, Barf Bag (currently erased), and Needle in a separate virtual world. They also erased Basketball.]