Is It Wrong to Try to Pick Up Girls in a Dungeon? On the Side: Sword Oratoria, Vol. 18 (manga)

As Lena suffers Valleta's wrath, Bete's scars begin to ache. In a fit of
rage, he charges
into enemy territory alone, invoking Hati, the powerful
magic that forces him to relive
his painful past. It burns all, leaving even
his heart reduced to ash. With Bete's fury
awakened, his enemies shall know
no mercy...