"Exchange all my flesh and blood for an immortal heart——" The young man embarked on a journey. He still doesn't know the identity of the disconnected man he fished out of the sea and worshiped as his elder brother; he doesn't know what an inseparable cause and effect sleeps in the seal card left by his missing father; he doesn't even know that there is another person who has come from the northern wasteland of blood and snow to pursue this unending fate with him! A sealed world, an immortal heart, the malice and redemption of the goddesses, the humanoid Hydras, can they wait for the knife that tears his heart apart? Passed the three outlooks, ambiguous/friendship orientation, yes for girls, yes for men, no for girls/boys, yes for kindness, no saint, yes for middle schoolers, lily... Maybe... I'm a newbie looking for guidance. If you think there's anything wrong, including typos, please comment and teach me!