The Hero Is Overpowered but Overly Cautious, Vol. 7 (light novel)

Feeling ill-prepared for the looming battle against Mash the Dragon King,Seiya returns
to the underworld to acquire some new skills. But every boongained from this dark
realm comes at a cost. While Seiya practices a stealthability, Rista turns invisible! As
he hones the power of darkness, disasterstrikes! Will Seiya be able to master these
new techniques before thedrawbacks wipe out his party?!