This will be categorized by their main affiliation by age without spoiling the stories.

【Monarch Sect】

Regis ▶ the one and only King of the Demons. No one knows his infernal name.

Riel ▶ the First Pillar and the owner of the Tower of Midnight. The Regis's right-hand man. Infernal name is Requimelle.

Sier ▶ the Second Pillar and the owner of the Tower of Nightfall. A famous alchemist in Nerov. Infernal name is Adiserrian.

Dion ▶ the Third Pillar and the owner of the Tower of Twilight. Known as the cruelest pillar. Infernal name is Arigiorion.

Kali ▶ the Fourth Pillar and the owner of the Tower of Dusk. The most secretive pillar. Infernal name is Kaliriara.

Vast ▶ the Fifth Pillar and the was given the Tower of Darkness. The only child of Regis. Infernal name is Iravastus.

Iona ▶ the daughter of Gorion and also helps in supervising the Tower of Twilight. The most secretive pillar. Infernal name is Alliona.