Shuu You

Shuu You is a senior official and an investigator in the Department of Civil Administration, therefore one of Reishin's subordinates. Due to the nature of his work, he often needs to go undercover and is skilled at disguising himself. He does not defer to any superiors who have not earned his respect, thus he is highly confrontational with Reishin, who is capable but unwilling to work and use his talents for the greater good. Though he had hope for Koyuu and became his mentor when Koyuu began as an official, Shou You became disillusioned when it became clear that Koyuu ended up limiting himself to working for Reishin. As a result, he does not hesitate to persecute Koyuu when he does not fulfill the duty of an official, despite being personally fond of Koyuu.

(Source: Wikipedia)