The Hero Is Overpowered But Overly Cautious, Vol. 6 (manga)

It’s time for the final battle against the Demon Lord! ...Or at least, it’s supposed to be, but Seiya suddenly goes missing while the rest of the party is taking a short breather in the imperial capital before the moment of truth?!?! They’ll have to track him down—and when Ishtar reveals the secret of Seiya’s past, his uncharacteristic rashness starts to make a lot more sense...