He has long hair, that he wears in two tails. He has a small goatee and a tattoo under his right eye. He is fully armored and fights with a sword.
Na Ki tends to have a relaxed and controlled manner. Never showing much expression however always seems to be paying close attention to those around him. Thus most likely the reason why Kan Ki chose him to watch the Hi Shin unit.
Before the beginning of the Battle of Koku You Hill, Na Ki was assigned as a representative and exchange commander of the Kan Ki army. This was for Kan Ki to have a better understanding on how the Hi Shin Unit operates.
After seeing how inspiring Shin and Hi Shin unit are, Na Ki decides to leave the Kan Ki army to join Shin. When Kan Ki asked for a reason for leaving; Na Ki claims that eating without feeling guilty is the best thing ever.