DxD: Matsuda? - Chapter 28: I’m Back?

During the day, she was his secretary, working very hard with excellent abilities. At night, she was his bedmate, trying her best to please him, and the two of them were very harmonious in bed. One day, this relationship was on the verge of ending. However, both of them had already become deeply involved and had grown accustomed to each other's presence, falling in love with each other. So...

A century after the Great Cataclysm, a brand new profession was born. They control iron, copper, phosphorus, gold, silicon, carbon...Gao Neng has awakened a sacrifice system and the first task he received is to sacrifice the most gifted girl in the military. The reward will be a shocking increase in his talent : Iron 100%, Copper 100%, Tin 100%, Silver 100%, Gold 100%, Phosphorus 100%, Sulfur 100%, Silicon 100%...

Asura – proud, warlike, cruel, heartless.

A young adult with a mysterious background follows his father’s prophecy and enters the world of «Rebirth», somehow managing to inherit the Xuanyuan Sword, and also unexpectedly obtaining the hidden class Asura.

Following the tracks of both virtual and reality he gradually discovers a secret hidden for the past billion years.

Asura, the class that used to shake the lands has now completely disappeared. He must now go on a journey to find the true meaning of Asura—until the day he transforms and becomes one with Asura.

- Description from Novelupdates

Tu Xiao'an dies due to an accident and he is luckily reborn as a snake with a system. As long as he gobbles down some preys, he could speed up his course of evolution and gain more power to protect his family.'Mom, Sis, I'm sorry. I'm so, so sorry for making you grieve!''One day, I'll stand before you again, out in the open, and take care of you!'