Boss Is Reborn After Everyone's Betrayal! - Chapter 3

Sen, the last and most powerful dragon left roaming the skies causing chaos and destruction across the land. When all hope is lost the human race call upon their last hope, a powerful witch. Unable to destroy the dragon the witch uses the last of her power to cast a spell. Sen has not been defeated but has now been reborn as a human.

After his parents died, Alex Roth had a plan: become a wizard. Through hard work, he was accepted into the world’s greatest university of wizardry—but fate had another plan.

On his eighteenth, he is marked as one of his kingdom’s five Heroes, chosen to fight the land’s great enemy. But his brand is 'The Fool', worst of the marks.

Rather than die or serve the other Heroes like Fools in the past, he packs up his little sister, his childhood friend and her cerberus, then flees for the university in hope of refuge, magic and to unravel the truth about his land’s evil.

There’s one small problem: The Mark tries to ruin magic while enhancing skills outside of divinity, combat and spellcraft.…

…that is, unless he can learn to exploit the hell out of it.

Is a flower demon with three hundred years of cultivation.

Shao Zi’s biggest wish is to beat up that egghead Scholar (shu sheng) that always comes to water plants at noon.

But when she got close and rubs her hands in preparation for action, she realizes that she’s clearly playing along to someone’s rhythm ah!

- Description from Novelupdates

The main character is reborn as a character from a game he played in his previous life. This character falls into ruin along with the villainess, spending the last of their years together. A man named Kururi Helan.