He enters the dungeon alone, using stealth items and avoidance spells. His goal is not to fight, but to catalog every monster’s breeding cycle, diet, and habitat.
In the crowded landscape of "Isekai" (transported to another world) and dungeon fantasy genres, power fantasies often follow a predictable trajectory. The protagonist is granted a cheat skill, they defeat monsters through superior firepower, and they accumulate fame and fortune. However, Geki Tsumi Dungeon desu ga “Sukiru: Hanshoku” de gyakuten shitai to omoimasu (hereafter Propagation Skill ) subverts these expectations by replacing the traditional power fantasy with a survival horror narrative driven by biological manipulation. Through its unique magic system, the series explores themes of resource scarcity, the ethics of bio-alchemy, and the terrifying fluidity of identity. He enters the dungeon alone, using stealth items
The narrative mixes dungeon crawler, base-building sim, monster tamer, and dark comedy. One chapter might involve breeding giant bees for honey; the next, negotiating with a mimic queen for breeding rights. The protagonist is granted a cheat skill, they
Enter our protagonist — let’s call him Kaito — a summoned strategist or reincarnated adventurer whose only notable unique skill is — i.e., “Breeding” or “Reproduction.” (roughly: It’s a Dead-End Dungeon
He sells surplus materials to fund better equipment and hire support staff (who never enter the dungeon with him).
In a genre crowded with heroes who kill first and ask questions never, Kaito builds. He breeds. He thrives.
(roughly: It’s a Dead-End Dungeon, but I Want to Turn the Tables with My "Reproduction" Skill ) is a dark fantasy/isekai series originally published on (the adult-oriented branch of Syosetu) before receiving a manga adaptation.