Adult PC Game: Super Mamono Sisters - Final by Shimofumi-ya Archive

One day, the Queen of Succubi awakened after a long sleep. Her powerful sexual energies transformed all the local village girls, cats, and monsters into succubi themselves...

"I've decided to have you for dinner. Come to my castle. Along the way, however, you'll be tempted by all sorts of monsters... try not to die before you arrive, alright?"

And so the sets out, tiny sword in hand, in pursuit of the succubus.
Was that determination in his eyes? Or was he under her spell...?