Ji-Hak Ryu

One of Castle's representatives, Ji-Hak is a cordial, if condenscending man who often works for the upper echelons of the faction, acting as an enforcer, assassin and overseer of operations. Despite that, he has a mostly neutral relationship with Shin and his faction, mostly limiting himself to observe them and even provide occasional aid. He seems to have in-depth knowledge of not only Castle affairs, but also of the world at large, and to have his own schemes underneath it all.