Physician's Odyssey - Chapter 6 - 3 Offences in a Row

Yuki, a high school junior, dies heroically saving a stranger and is reincarnated in a fantasy world, where he discovers an extraordinary and unrivaled power.

A cauldron, a secret forging method, and his blood created an ultimate weapon. The youngest Sword Crafting Master on Earth had been reborn from another world. With the Nine Yang Divine Furnace and a scroll of Divine Equipment, he was like a fish in water, standing at the pinnacle of the martial way. There were tens of thousands of clans, billions of cities, and countless experts. He was the master of ups and downs!

What happens when a fanfic author with a habit of lying and scheming suddenly finds himself as a self insert during Duelist Kingdom? What happens when you have Yugi, Joey, Kaiba, and the rest encounter someone who knows all about every major player in their saga... and sees no problem with abusing said knowledge? Chaos, dear reader. Sweet, sweet chaos

Jiang Xunyi had transmigrated into a book many years ago, and always tirelessly maintained the requisite accomplishments for a villain.

After finally completing the ultra-difficult task to allow the male protagonist to kill him, an OOC warning had appeared out of the blue——

Error in the actor’s lines, the character role has collapsed, the assigned task has not yet been completed, opening the Rebirth System!

So, he gloriously became… a second idiot son about to be sent to his death.

Lazily idling away the days after changing his identity, he noticed a world-changing difference.

His best friend, the male protagonist, Yun Xie was actually secretly in love with him? Are you kidding me?!

- Description from Novelupdates