He was born when Washesh was having a child, but some Malleo DNA got into the womb and made the child half Malleo, half Waweegee. Walleo was named when Papa Waweegee remembered his old enemy, Wario, so he named his son Walleo.
Member of the UMAEdit
In search of new members, Dark Tails entered hell. While in hell he met Walleo, Dark Tails then promised Walleo that if he joins the United Monsters of America, he will got all the money in the world. Walleo then agreed. Later, Walleo stars a rivalry with a member of the Skodwarde Squad called The Hash Slinging Slasher, in the battle, Walleo wins defeating the killer.
The T.D SquadEdit
When walleo knows about his brother Waweegee was injured, he gets his revenge killing Tails Doll and imprisoning his soul in Satan's Ass.
After Giywardeaugh death and the end of the war, he and his brother Waweegee made a party for Dark Tails and the Death Squad.