Fate/Grand Order -Epic of Remnant- Pseudo-Singularity III: The Stage of Carnage, Shimousa - Seven Duels of Swordmasters volume 4

With the Castle Toke crumbling all around them, Ritsuka and Musashi's battles against the seven deadly Heroic Spirit Swordmasters continue. Their third opponent is Assassin of Paraiso, a shinobi cursed by divine power that threatens to consume her very flesh. Can they emerge victorious? And even if they do, what of the demons who lurk in the shadows as rivers run red and bodies pile to the sky?