Throne of Astrea
He failed his university entrance exams four times, got arrested by his girlfriend's parents for her
murder, and died in a traffic accident on the way out of the country.
Not exactly a hero's origin story.
But death, it turns out, was the best thing that ever happened to Lucius — because on the other side of it he woke up as Julius Astrea, infant prince of a kingdom where someone is already trying to kill him, his mother died giving birth to him, and his grandmother turns into a dragon when she is annoyed.
He has no power. No allies. And absolutely no idea which story he has reincarnated into.
What he does have is a photographic memory, a deeply unhealthy relationship with books, and the slowly dawning realisation that the assassins who have been trying to kill him since he was two years old are not human.
Julius does not want to be king. He does not want to be a hero. He would very much like to survive long enough to figure out what is actually going on.
Unfortunately, the world has other plans.
Throne of Astrea is a slow-burn isekai fantasy with a protagonist who survives on intelligence rather than power, a grandmother who could destroy a small army, and a magic system with no blue boxes, no skill notifications, and no convenient cheat abilities.
Just a boy, a dragon, and a kingdom full of things trying to kill him.