Traveling Through a Different World, the Witch Turned Out to Be My Ex-Girlfriend

[Single female protagonist] + [Western Fantasy] + [No system] + [A little bit of anime style] After experiencing that war, Herbert, who lost recognition of the significance of military existence, died in the battle amid constant condemnation and guilt from his conscience. As expected, he and his men went to hell. After staying here for 200 years, he inexplicably made a contract with a female imp. As long as they help her complete the contract, they can get what they want. So a war for death began...