(Counterclockwise starting from top-left.)

Sadi: Ultimate Sadist & Fire Corruption Leader

Pina: Ultimate Trap & Water Corruption Leader (Seriously. He's a boy.)

Roger: Ultimate Speedrunner? & Light Corruption Leader.

Kakui: Ultimate Wind Corruption Leader

???: Ultimate Dark Corruption Leader
(Sadly, I don't know this woman's name.)
April 15, 2018 Edit: I saw in one of the posts in Gacha Resort Group on Facebook, that this woman's name was Curse. Still a theory, but I'm just gonna go with that.
July 8, 2020 Edit: Seems like Coru is her official name, after all.

TBH, I want a male version of the Dark Corruption Leader's hoodie.