Kill to evolve: A system that demands blood - Chapter 7: power extraction

As the heir apparent of the Ye family, Ye Xuan went through fire and water for his family, but Ye Lang, who had just awakened his Divine Soul, usurped his place. In order to keep his position, Ye Xuan challenged Ye Lang to a Life-death Duel. With the broken Dantian, would he win this fight? The black ring his mother left brought him a great opportunity: Realm Hell Tower, where he met a mysterious lady, who told him to look for nine Daoist Laws to enhance his strength and gave him the Spirit Heaven Sword. Could Ye Xuan find all the Daoist Laws and become a powerful swordsman?

- Description from Novelupdates

The world is full of mysteries. Strange, seemingly unexplainable events occur more often than we may realize. A young boy may catch an illness no doctor can explain. An office may catch fire for no apparent reason. And perhaps, someone may die a sudden and unexpected death – their bodies blighted beyond recognition.

Three years ago, in the land of Reinbulk, a Legendary Hero was summoned in the Kindom of Leezalion and he succeeded in repelling the Demon King. Now, five students are summoned back into Reinbulk by the Kingdom of Luxeria to fight against the Demon King and the demon army. Unlike the other heroes, Yashiro Yuu has no magical affinity and the Luxeria Kingdom has no intention on acknowledging his existence or returning him to his world.

This is a very interesting thing. It is obviously dim and black, but it can emit a golden light, which makes people deeply fascinated by it…

- Description from novelbuddy