Phantaminum

Phantaminum is a mysterious and highly dangerous Irregular, currently in the 1st ranking. He is famous for creating the stereotype against Irregulars. He is presumably the most powerful entity in The Tower, even dominating over Guardians.

Origin of the Sobriquet
Phantaminum appeared suddenly in the Tower and broke into the Zahard's inner palace, killing many royals and courtiers. He succeeded in breaking all of the lines of defense and ultimately faced Zahard but he disappeared without a fight. His mysterious appearance and disappearance from the Tower left many unanswered questions, which is how he got the sobriquet, "Riddle." Another reason is his style of combat. It is said that he had a freewheeling and desultory combat style and had used a weapon that was not seen anywhere inside the Tower. Most of the eye-witnesses either died or lost their minds with fear, so the stories were not accurately reported.

About
The negative views toward the Irregulars have grown because of him and these views had a big impact on Urek Mazino when he climbed the Tower. When Phantaminum broke into the palace, it is said he met Yuri Zahard in the inner palace. There is a great diversity of opinion as to why he didn't kill her. Yuri Zahard didn't say anything about the matter except that 'He was a messy one.'

There were a lot of objections in the Rank Admistering Office about giving Phantaminum the 1st ranking, who had disappeared after the attack of the palace of Zahard and had become inactive. But everyone agreed his impressive strength alone was overwhelming. As a result, Phantaminum became the No. 1 Ranker by showing himself in only one battle, dragging the 'Red Tower' Enryu down to 2nd rank.

Current status
He was seen very little in the Tower after the attack of the palace, and most of the stories are rumors, therefore it's hard to confirm any of the stories. There's a rumor that he is in a cat-and-dog terms with Urek Mazino, but it is not confirmed. All in all, Phantaminum is a monster whose information starts with a riddle and ends with one. Every Ranker is on watch for the movement of this monster.