This Eroge Won't Make Me Fall! - Chapter 12 12: Beginning Of Planning

Reincarnated without memories, given a second chance as a chimera with a limited lifespan. Leon struggles through his strange new life. He attempts to improve his dungeon and evolve himself to live longer and become the strongest Dungeon Master—no. The Dungeon Overlord.Helped by his Dungeon System: the mysterious Ifrit, Zafira a Level 100 Succubus Queen, and his band of trustee goblins. Leon aims to overcome his limits, survive and reach the pinnacle of the world. Whether through trade, domination, or tricking the hero's beautiful party members into becoming his private mercenaries.Leon will face the weakest and strongest beings in the magical world of Umbra and surpass all!

In the middle of a deserted island, a small boy wakes up with two sets of memories: one from his few years of life and the other from a man who lived to adulthood and achieved great things. When he least expected it, a powerful master appeared on the island and took him in as a disciple, revealing a shocking fact: magic exists in that world, and, thanks to it, humanity managed to conquer the galaxy.

With a marriage contract forcefully done, he married her, and all she could do was comply, and resent him deeply for that and for all the following misunderstandings they faced.
However, it was already too late when she understood she actually loved him.