ATG: My genius is almost frightening! - Chapter 55: Lemons? Lemooons!!!

The rule had always been this way: the strong over the weak, the rich over the poor. Mark knew this, he'd even experienced it.After his boss fired him for discovering the affair with his girlfriend (who also worked at their small gaming company), Mark vowed never to be humiliated like that again. He wanted to rise above everyone, to become the world's top player, the one who made the rules and decided everyone's fate. But that was wishful thinking. He was just a heavyset, nerdy guy with some programming skills and a large appetite. What else did he have going for him?Hit hard by this reality, jobless and dumped, Mark withdrew into gaming, which also became his source of income. One day, after leaving a bad review for a game he played and streamed, he received a strange reply from the game's creator. Suddenly, Mark found himself transported to Aetherium, the world of that same game, as Magnus Lancaster, the young lord of a crumbling territory.Now, with this new beginning, he vowed never to be weak again, never to leave his fate in someone else's hands.

This is a story of a modern man returning to ancient times, returning to a real world without any extraordinaryness, and slowly rising by relying on the ability to attribute all data.

- Description from novelbuddy

Roy died during a war against the Evil God Cult, but somehow, he returned back in time to 30 years in the past where he was just a boy who awaken his summoning magic.