How Can He Be the Protagonist If He Is so Cowardly?

When I woke up with a hangover, the sky split in two. Half blue, half dark red. There is an extra thing in my body. It said I signed a contract with it. If you fail to complete the task, your life will be yours. The first mission: protect a girl in a fishing village. But after entering the village, I discovered—— There are no women in this village. None. And something is crawling on the streets at night. The sound of scales rubbing against the ground came from far to near. Guchi... Guchi...