It would be fun if we hit Endeavor with the DFO stick

Enji grew up knowing that his dad would give him anything he wanted- if he spun it right, and fully committed. If he didn't convince him, or faltered at all, then his dad won instead and that was a bad time.

He was allowed to become a hero because he said he specifically wanted to beat All Might, humiliate him at his own job before AfO took him down. And then he threw himself into getting strong enough to do just that, though AfO doubted it ever would work, it at least seemed like Enji thought it would, so he allowed it. The first time Enji met All Might in person, he saw no less than four of his father's operatives watching in the crowd, and knew he had to be cold, knew he'd never have the freedom to ask for help. And he'd gotten this far on his own, he'd gotten more freedom than he'd hoped for as a kid, so this was enough. this would be enough until All Might killed his dad, surely.

But then Enji fell in love, and knew that would never fly as a reason to start a family AfO was not involved in. He wanted to leave well enough alone, break it off for her own good- but Rei had her own family troubles, and Enji had managed to come up with a plan for everything else so far... so they staged a quirk marriage to satisfy all parents, Enji claiming it was to create a quirk strong enough to beat All Might. AfO raised a skeptical brow, but decided to let him try and fail, promising his best doctor and expert in quirk sciences to take care of Rei's and any children's health.

Now that Enji knew that AfO would absolutely be checking in on the children, he knew he'd be asking them about him as well, always keeping a close eye. Which means they couldn't tell the kids that it was a fake quirk marriage or that Enji didn't care about forcing them to beat All Might one day- AfO would find out, and Enji didn't want to know what his father winning would entail this time. Rei pointed out that they could just... not tell the kids anything, and if AfO asked, Enji could claim it was kinder to keep his children in ignorance until they were old enough to safely train, and even then, AfO wouldn't expect the kids to know everything about the terms of the marriage that he was told. But, stubborn Enji insisted that he knew his father, and this was the best way to keep the kids safe and the family together.

He was somewhat right- AfO had been keeping close tabs on Touya the whole time, acting as an online friend, and was utterly convinced by what Touya passed on- but also irritated by Touya's treatment as the oldest brother. (he's projecting) and since Enji clearly isn't even acting like a father, surely he won't mind AfO intervening on the children's behalf and keeping everyone happy, right? And if, say, hero society collapse entirely one day... well it's not like AfO didn't warn Enji all those years ago it would happen, and to try to reach number one hero as quickly as he could to actually enjoy it before he had to come home.