15 Blades: The Legend of three madman and a girl

15 Blades: The legend of three madman and a girl, also called 15 Blades, Is the first realeased story in the 15 Blades saga, it was a joint author story written by all four authors in the saga.

Plot
The four protagonists go to the borderlands of the hell, called the Nexus. They are brought here to fight the lord of time, who wishes to alter time to remove their existance. They fight him but do not manage to stop him, and he sends four remnants of himself to four different timelines, triggering The 15 Keys, Follower of the gods, Fate By Blades and The adept series recounts.