Doma, the Upper Rank Two demon in Demon Slayer, is ultimately killed through the combined efforts of Shinobu Kocho, Kanao Tsuyuri, and Inosuke Hashibira. Shinobu Kocho initiates the battle and sacrifices herself by injecting herself with a heavy dose of wisteria poison, allowing Doma to absorb her body. This causes the poison to enter Doma’s system, significantly weakening him. After Shinobu's death, Kanao and Inosuke join the fight and help in delivering the final blow that decapitates Doma, killing him.
Key Details:
- Shinobu Kocho cannot kill Doma by severing his head directly due to his regenerative abilities, so she uses poison as her weapon.
- Knowing Doma would eat her, Shinobu continuously ingested the poison to ensure killing the demon from within.
- After Shinobu is absorbed and dies, Kanao and Inosuke finish the fight by decapitating Doma.
- This teamwork approach was necessary due to Doma's immense strength and regeneration which makes him nearly impossible to kill alone.
Thus, Doma is killed by the combined actions of these Demon Slayers, centering around Shinobu's poison strategy and Kanao and Inosuke’s final strike.
