Irregular

An Irregular is a being that has entered the Tower without granted permission of Headon. Irregulars are all famous for being extremely powerful and have wreaked havoc and terror within the Tower.

Zahard & 10 Familes
Although King Zahard and his men came into the Tower from the outside world at ancient times, it was before the testing system was invented. They are not considered as Irregulars because of this.

Known Irregulars
Baam

Lahel

Phantaminum

Enryu

Urek Mazino