Nauk was forced to join the Legions when he lost control of himself and attacked a merchant. He was given the choice of military service or criminal punishment.
Nauk was in the War College the year Catherine Foundling temporarily entered it. He was part of Rat Company, and in Catherine's first training battle he was one of only a handful of people to escape Juniper's opening attack.
Nauk is described as being intelligent, but preferring to be aggressive and take the initiative rather than wait and let his enemies take initiative.
He also has an unusual difficulty in controlling the red rage, which is something of a liability in one of his rank. However, he is otherwise competent and always had Nilin to cover his personal weaknesses. Nauk's personality has become increasingly violent after the death of his friend. He jumps head first into battle ignoring the danger's of combat. After his revival his personality has become erratic although he still functional enough to process thoughts, he is only a moment away from violence. He has become a shell of himself of what was salvaged he now only receives joy from serving the legions(no doubt by design).
Nauk had a very close friendship and working relationship with Senior Tribune Nilin. Nilin was always the calmer, more thoughtful one who kept Nauk from letting his emotions get the better of him. He took Nilin's death in the Battle of Three Hills very poorly, entering a rage and attacking the soldier who brought him the casualty listing before being subdued by Catherine.
He also has romantic feelings for Senior Sapper Pickler, putting him in competition with Tribune Robber. Pickler has admitted that though she has little interest in either of them (or anyone else) romantically, she enjoys the reminder they provide that she isn't under the thumbs of the Matrons and could start a relationship without their approval if she wished.
Since his resurrection via Warlock's sorcery he has vague sense of the memories and relationships he once possessed. Now though he has none he only has the legion to comfort him.
An orc who was taught at the Academy and is well versed in legion tactics. He also has what is called the "red rage" this is trait where orcs fly into a reckless fury. In Nauk's case he is untrained in controlling his rage thus when under enough emotional stress he can potentially harm both friend and foe. After his resurrection though it seems that he has lost the red rage maintaining a cold and balanced emotion.