Reincarnated In A Novel As A Pathetic Side Character

What happens when you wake up inside the world of a novel you read?

The same thing happened with Shion, a man in his early twenties.

Although he was excited at first but all that excitement was gone the second he realised the character he was reincarnated into.

It was not a mob but even worse! He was inside the body of Zephyr who was a side character.

You might be thinking what's wrong with that? But you should be asking what isn't right about it.

He was a pitiful soul born with a weak body. Was despised by his family. He was framed for cheating on his girlfriend by his best friend.

Later, he married the dying princess who he later fell in love but things didn't go as well as she was raped by his best friend in front of him.

In the end, he died.

But Shion didn't want this to happen to him so he started working out and with the future knowledge and a system.

Will he be able to change Zephyr's fate?