Back in ancient times, a human named Aaron used a staff and sealed a lucario within it to take care of the Tree of Beginnings. Eventually the old world ended as humanity fell, leaving the staff to never be seen again. In time pokemon began making their own kingdoms, technology and societies. And the staff would eventually be picked up by traveling merchants who sold it to a pawn shop where it remained.

From within the staff, Lucius began to utterly resent mankind and decided to sleep within the staff and plot revenge against them, even Aaron who promised to come back for him, training within the staff to fight and learning to use his aura to transform other beings into diapers, intent on turning the human he sees into a diaper.

Several centuries have passed and Lucius was planning to give up hope of ever being free. Fortunately, the staff was purchased by some nobles to offer as a gift to the king by presenting it to Sol, one of the Elemental Knights. As Sol presented it, a pokemon from the old world emerged, much to everyone's confusion. The Lucario opened his eyes and was very confused by the world he's in as there were diapered pokemon everywhere, some wearing regulars, others wearing other pokemon.

Guards were ready to arrest him, but Sol called them off and wanted to ask him some questions. He only agreed since it was another Lucario and he can tell from the Aura he seemed trustworthy. He introduced himself as Lucius Calisto, that's all he can remember. He was asked if he has any friends or acquaintances, but refuses to trust others. Sol didn't want to see a pokemon of his talent and combat go to waste, so convinced him to try out for knight as he'd love to have him in the Steel unit.