Personally, you normally would think change his title to Brigadier General instead of Commander? I know it's just a ideal thought but sometimes it's hard to determine some npcs by actual rank and who they are senior and junior to.
At least they call Thalan a Colonel since he as a Colonel is senior to a Lieutenant Colonel and junior to a Brigadier General so would Commander Barvian be a Brigadier General unofficially? I don't know.
This guy is for one of the progression missions "Safe Passage". The task steps are as follows. Speak with Scout Fathim. Make your way to the refugee camp. Destroy the raiders attacking the refugee camp. Speak with Colonel Thalan. Protect the refugees. Let the Colonel know when you are ready to move on. Clear a way into the forest ahead. Scout the path to the southwest. Scout the path to the southwest. Protect the refugees. Speak with Colonel Thalan. Speak with Commander Barvian.