Bog Standard Isekai - Chapter 42Book 4. .5

Possessed an extra with a single rune.After obtaining 7 runes directly according to the original Hidden Piece…A fraudulent rune called [Rune Hunter] was created.

To treat her sick brother, she was forced to marry him in place of her cousin, who was disfigured and paralyzed. At first, their relationship was purely transactional, with neither caring much for the other. But after going through a lot together, they fell in love with each other. He doted on her deeply.She was considered an ordinary person by the world, but it was later discovered that she had multiple identities - a mysterious underground boxing champion, a highly-skilled doctor, and a mysterious and renowned composer... He also realized that their fates had been intertwined long before they met.

She was the head of a powerful, medicine-orientated aristocratic family.

Crossing through a millennium, she ended up in the body of the General Household’s “trash” young miss, whose engagement with the Crown Prince was just broken as she suffered under everybody’s taunts!

In the drafting feast, she was re-engaged by the Emperor to marry the famous disabled prince!

Everybody laughed, a blind trash with a disabled wastrel. What a perfect match!

However, they didn’t know that in her hand, she grasped the long-lost primordial pill recipes! Her practice in medicine had reached the apex! Her contracted beasts were unique in the world!

What was the most frightening, was the disabled prince she was engaged to…….

A black-belly full of dirty tricks, with a heaven-opposing cultivation physique, he defeats all geniuses!

In his wheelchair during the day, yet entangling her in bed as he trained his waist muscles… MF! Is he really crippled!?

- Description from Novelupdates

Our protagonist Caam is a man from Earth that was reincarnated into this world as a demon. In order to survive, he spared no effort in avoiding the sparks of battle and without noticing it, he became strong himself.