Enryu entered the Tower during Zahard's rule. His most interesting achievement, the slaying of the Guardian of the 43rd Floor revealed to the people of the Tower that Guardians, originally thought to be immortal, were not absolute beings.[1] It is unknown why Enryu killed the 43rd Floor Guardian, however a huge thorn was left behind at the site where the Guardian died.
Before this feat Zahard was #1 in Ranking by then, although his inactivity led to him being pushed down to 2nd place by Enryu, who took over the 1st place at the time because of this.
Enryu became the No. 1 Ranker with the nickname of "Guardian Murderer".[1] Later on, Phantaminum entered the Tower. With the Zahard Palace Intrusion Incident, Phantaminum quickly took 1st place, pushing Enryu and Zahard down to 2nd and 3rd places, respectively.[1]