Demon Lord Simulator

I open my eyes and find I've lost my memory. I'm middle-aged, and there's Lazarus soaking in my thermos.

Well, I wake up one morning and become a mentor without even feeling a thing.

And now, on the other side of a door, someone says he wants to find Ra's al Ghul and study under him.

Uh-oh. This is bad. All I can do now is hold my thermos and drink water.

There's no time to explain. Simulator, start up! Hurry and teach me how to be a mentor so I can train this young man named Bue Wayne!

And then...

The Batman Who Laughs: I expected all of this. Surprised, my dear mentor?

Vampire King: What, wasn't the destruction of humanity what you wanted?

Lone Bat: You'll help me kill her, won't you?

...Is something wrong with these students in the simulator? I clearly taught them along a path that nurtured virtue, intellect, physical fitness, aesthetics, and practical skills. How did they all turn out as dark as coal?

Anyway, after raising a bunch of people in the simulator for practice, I trained the student I was most proud of in real life, and looked forward to seeing him accomplish great things.

Until my subordinate reported that after Bruce returned to Gotham, he was partying every night with eighteen models, and was also entangled with Batman.

Me: ...

After I arrive in Gotham and see the young man beneath Batman's cowl, I fall silent. He is just as shocked. "I saw you die with my own eyes!"

Tsk. Students in this world are so naive and easy to fool.

Batman thinks his relationship with Ra's is that of lifelong archenemies.

The League of Assassins sees Batman as a succubus who has bewitched the Demon Head. Terrifying indeed.

And Ra's's view of Batman...

His ambitious young disciple, his sharp-edged opposition, the greatest enemy he trained with his own hands.

--Important Content Warning--

No CP. Readers with any trigger points are advised not to read. A rotten old man relentlessly emotionally manipulates various superheroes, sometimes successfully and sometimes disastrously. As usual, it's all twisted madness and bitter, agonizing love.

The demon who would destroy the world and the hero who would save it.

Theme: Retirement life is nice, too.