A Hentai System in the World of Danmachi - Chapter 124 - 123 - Mother.

I was betrayed in my first life.A cripple, broken and discarded—I died after catching the one I loved in bed with the only person I ever called a friend.That was the start of real torment.When I woke up, it was in another world.A goddess stood before me.She told me I could go back.Back to my world.Back to everything I lost.All I had to do… was play my part.The side character.And I did.I followed the script.Played my role to perfection.They hated me.Mocked me.Used me.Again and again.But I kept going. Because I believed her.Because I wanted to go home.Then one day, I found out.The hard way.It was all a lie.There was no going back.There never was.She used me.Again.Just like everyone else.Thrown away like trash once I outlived my usefulness.That was the day something inside me snapped.And so, I made a vow.I would take everything from her.I would enslave every single heroine she chose.And I would kill the hero she placed all her hopes on.If she wanted to protect this world…Then I would burn it down.But the more I tried, the more things started to change.And then one day—I found one of the heroines.One of the hero's yanderes I had enslaved.She stood there, trembling, a knife in her hand.“You’re not going anywhere,” she whispered, eyes wild.“I won’t let them have you. You belong to me.”...What. The. Fuck. Is. Happening?!

The scum’s or villain’s long road of transformation was tentatively set to the world:
The abandonment of the educated youth’s wife (Completed)
The hidden marriage of the scum film emperor (Completed)
The best brother in the world (Completed)
The Phoenix male who destroy the bridge after crossing the river (Completed)
The treasonous general (Completed)
I’m an honest man (Completed)
To become the top scorer in the School of Agriculture (Completed)
The soft rice man’s self-cultivation (Completed)
The whole world is reborn (Completed)
I want to survive on a desert island (Completed)
The stallion male who has seized the opportunity (Completed)
The perverted self-salvation (Completed)
The spring of the loafer (Completed)
The misplaced life (Completed)
The miser career (Completed)
The ghost is out of feeling (Completed)
The Queen’s favorite husband (Completed)
The vicious girl with her godfather (Completed)
I want to be a good person (Completed)
I does not tear up the family (Completed)
The perverted common plant (Completed)
The Mary Sue’s men (Completed)
Every time I was reborn, someone wants to kill me (Completed)
The old people’s counterattack path (Completed)
The global evolution (Completed)
When I became a net red (Completed)
For you, good person (Completed)
His heart had white moonlight (Completed)

- Description from Novelupdates

He crossed over to a new world where humans have magical power. They are called warriors. They use their power to kill the monsters that appear out of nowhere. Dragons, Dungeons, and Magic users are pretty common in this world. If you want to live in peace, you need to have that power. You can also become a powerful clearing dungeon.

In this dangerous world, he has a system that can help him grow stronger. But he didn't want to be a high-profile warrior who attracts much powerhouse attention or become a lab rat. He wants to be Low-profile and grow strong using his system.

I made a game.