Synopsis

After nuclear winter wiped out civilization and twisted nature into something hostile and unfamiliar, teenager Ren Xiaosu scrapes by in the wasteland with nothing but grit and his younger brother at his side. He and his younger brother, Yan Liuyuan, survive outside the fortified walls that the remaining human settlements hide behind: no status, no resources, just each other. Then Wall 113 collapses in an earthquake, and whatever fragile sense of safety existed gets ripped away completely. This 26-episode ONA from Flying Fish Studio picks up from there as the brothers are thrown into a world of mutated creatures, desperate scavengers, and a power system that ties supernatural abilities to human willpower in ways that feel genuinely fresh. What makes it work is the relationship between Xiaosu and Liuyuan: it's not just a survival story, it's about two brothers who refuse to let the apocalypse turn them into something they're not. The world-building is dense, layering sci-fi and fantasy elements without feeling cluttered, and the tone stays tense without becoming exhausting. If you liked Attack on Titan's walls-and-what's-beyond-them setup, or the post-apocalyptic brotherhood vibes of Seraph of the End, this scratches a similar itch while doing its own thing. It also shares DNA with Kabaneri of the Iron Fortress in how it handles action within a collapsed society. Based on a web novel, so the source material runs deep. Worth your time if you're into grounded survival stories with a supernatural edge.