Han Sen planned to practice in the mountains. He didn't need to practice Teeth Knife, but there were too many spies occupying the base. If Han Sen stayed there without practicing, people might grow suspicious.
So, Han Sen headed into the mountains to train. But instead of practicing Teeth Knife as he had told everyone, he began to work on the Dongxuan Sutra.
His Mutant Blood and Jadeskin had reached Viscount class, but the Dongxuan Sutra and The Story of Genes hadn't. The Story of Genes couldn't be leveled up through mere practice, so he could only focus on the Dongxuan Sutra for now.
Han Sen didn't take anyone with him this time. He planned to push himself hard in order to breakthrough, which would make it dangerous to have others around him.