Aiming to expand the experience of being a king and ruling your kingdom, A King's Court will add more titles, events, traits, court positions, decisions and tweaks.
The Justiciar is currently using another set of actions taken from other court positions like Spymaster, currently he has Postelyze and Scheme but will in the future get his own custom actions.
The Justiciar is another word for Judge or Supreme Judge. He will act as the law in your kingdom.