Maou ni Natta node, Dungeon Tsukutte Jingai Musume to Honobono suru  

Now I'm a Demon Lord! Happily Ever After with Monster Girls in My Dungeon, 魔王になったので、ダンジョン造って人外娘とほのぼのする

I understand you're asking about the background of your current situation. It appears that you have become the guardian of a dungeon and a Demon Lord. You found yourself in a dangerous world with monstrous creatures lurking around, fighting for their survival. Despite this, you decided to focus on developing the dungeon as a means of staying alive. As you progressed through your journey, you encountered a supreme dragon girl and a vampire girl, with whom you shared both laughter and anger. You spent your days doing what you enjoyed in this new world. Can you tell me more about how you became the guardian of a dungeon?

Maou ni Natta node, Dungeon Tsukutte Jingai Musume to Honobono suru has been published digitally in English as Now Im a Demon Lord! Happily Ever After with Monster Girls in My Dungeon by J-Novel Club since May 10, 2023.