Machiavellian Secrets

Su Jin returned to the capital as "Mr. Tianji" and stayed in a remote inn. He has a thin face, deep eyes, and an extraordinary temperament in his movements. At night, he encounters an assassin in the inn and easily resolves the crisis, implying that he has extraordinary skills and his identity remains a mystery. In the inn, a romantic woman approached Su Jin, and there was an ambiguous conversation between the two. The woman tentatively asked about his identity, but Su Jin avoided talking and just smiled faintly. Suspense: What is Su Jin's true identity? Why did he return to the capital?