MC is born to horribly abusive parents. He escapes when he is 10, becoming a mercenary, and rises through the ranks. He then is found by a famous mage, told he has magical abilities, and studies magic at the academy. After graduating with a PhD, he becomes an imperial guard, and then becomes a confidant of the emperor. At some point, emperor orders him to take his daughter on a week long vacation in another country. During that vacation, the emperor "dies" (i.e., is mu*dered by the first prince). To protect the princess (who is 10 at the time), MC becomes her father, using mind control to make her forget the past (she was a traumatic wreck and if he didn't there was no way he could protect her). He then raises her like a father - giving up all his wealth, status, and history, becoming a construction worker to make money to raise her; all the while, the new emperor is after her to force her to marry creepy Duke character.

I think a lot of people might dislike this novel, calling it a g*ooming novel. The princess is hopelessly in love with MC, even though he has a girlfriend and started raising her when she was 10 and he was 25. I can't believe someone previously tagged this with shounen - she sexually assaults MC in his sleep every night (using magic to make sure he doesn't wake up), and while she hasn't gone all the way, she m@sturbates on him and seemingly takes care of his needs.