The official Twitter responsible for Gangan Joker revealed that chapter 45 of the Ragna Crimson manga is approaching the story's "final battle."
Synopsis
Ragna is a dragon hunter along with his partner, the strongest dragon hunter, Leo. He didn't have much talent for hunting dragons, but decided to entrust his entire life to her. However, he was shown the feeling of true despair by his future self, about what would happen if he remained weak as he is now. With this, it seems that the dragon shinigami appeared earlier than in the original story, but will that be enough to change the future?
The Ragna Crimson manga launched in Gangan Joker magazine in March 2017, and its 8th volume was published by Square Enix on January 22nd of this year.
Source: ANN

