Anti-Wally was a very...strange child. He was very hyper and obviously not that bright, to put it lightly. He was often made fun of because of his teeth. He met Anti-Carrey middle-childhood-ish and immediently took a liking to her.
When Anti-Carrey got kicked out, she dragged him with her, and he, who typically just goes along with whatever Anti-Carrey says or does, agreed. They both lived like blue hobos for a while until Anti-Carrey killed the genderbent leader of the Anti-Fairies and took control of genderbent Anti-Fairy World when they were both finishing their teen years.