There was a novel that he couldn't remember the specific content of. The main character had a younger sister. He only remembered that the main character used the virus from Resident Evil to create a tyrant.

This is a very famous novel. I don't remember the specific name, but according to the plot you provided, I can roughly guess that it might be " Demonic Ancestor " or " Battle Through the Heavens." The main character might be a character called Xiao Yan, who lived with his sister on a mysterious continent. In an accident, Xiao Yan came into contact with a virus called the 'Black-Corner Region'. This virus could cause a person's body to mutate and become incomparably powerful. Xiao Yan used this virus to create a monster called Tyrant. He used the Tyrant's strength to conquer other factions and achieve his ambition. However, the power of a tyrant was not without a price. He might sacrifice many innocent people, and even his sister might become a sacrifice. This novel was very popular and had a large number of fans. It told the story of a world full of magic and battles, where the protagonists constantly grew up and challenged powerful enemies to finally achieve their goals.