Shen Qingqiu is the protagonist of The Scum Villain's Self-Saving System. He is the Qing Jing Peak Lord and a cultivation master.

Original Shen Qingqiu
Shen Jiu, the original, had a sharp and calculating mind and was not above using devious tricks. Even as a slave child, he fought using such underhanded means as poking his opponent's eyes.

He was often cold to others and carried himself in an aloof and elegant manner, as if he was hard to ruffle. This gave him the sense of being an unreachable immortal as described by Luo Binghe. He was also described by Luo as someone bitingly sarcastic.

Post Transmigration
Shen Yuan, who transmigrated into the body of Shen Jiu, is a sarcastic, somewhat nerdy millennial. He's a little spoiled, being the child of a rich family in his first life, and more than a little dense.

He has a colorful internal dialogue, arguing with the SYSTEM and complaining about his circumstances. Around Shang Qinghua, this part of his personality is especially obvious, as he yells at the author for the ridiculous plot points he wrote that the both of them now have to deal with.

(Source: The Scum Villain's Self-Saving System Wiki)