The owner of the strongest organisation

Sai, left his home when he was 18 to study in a better place but, due to an incident in the first year of his college, he got involved in the feud of a local gang. later he was expelled from the college as well and sent to jail for few months. Now, seven years have passed since that incident and his family who still thinks he's studying abroad is happy because he's coming back after full seven years. But, what they didn't know is that the 18 year boy innocent who left his home has been dead for many years and the person who's coming is the owner of world's strongest organisation.