During their decade-long quest to defeat the Demon King, the members of the hero's party—Himmel himself, the priest Heiter, the dwarf warrior Eisen, and the elven mage Frieren—forge bonds through adventures and battles, creating unforgettable precious memories for most of them.

Ever since the death of his father, the burden of supporting the family has fallen upon Tanjirou Kamado's shoulders. Though living impoverished on a remote mountain, the Kamado family are able to enjoy a relatively peaceful and happy life. One day, Tanjirou decides to go down to the local village to make a little money selling charcoal.

Centuries ago, mankind was slaughtered to near extinction by monstrous humanoid creatures called Titans, forcing humans to hide in fear behind enormous concentric walls. What makes these giants truly terrifying is that their taste for human flesh is not born out of hunger but what appears to be out of pleasure. To ensure their survival, the remnants of humanity began living within defensive barriers, resulting in one hundred years without a single titan encounter.

Surrounded by a forest and a gated entrance, the Grace Field House is inhabited by orphans happily living together as one big family, looked after by their "Mama," Isabella. Although they are required to take tests daily, the children are free to spend their time as they see fit, usually playing outside, as long as they do not venture too far from the orphanage—a rule they are expected to follow no matter what.

When approached by a fellow death god tempted to visit the human realm, Ryuk recounts his own journey to the other side and the story of Light Yagami—a brilliant young man who impressed him there.

Now that brains and brawns have united forces, the next step in Senkuu's plan to unravel the mystery behind the green light that once petrified humanity is to go to the other side of the Earth and investigate its origin. However, to achieve this, Senkuu must first build a ship.