Alpha and Omega 3: The Great Wolf Games
Nars first appears as the coach of the Northern Pack team, demonstrating shades of his antagonistic side when he orders his son, Fleet, to return to training. Another early sign of Nars' antagonistic nature is shown when Fleet's fellow teammate Magril refuses to say anything out loud, instead whispering into Fleet's ear and depending on him to speak for her. It is revealed that due to Nars' extremely aggressive approach to their training, Magril is terrified of him, and thus refuses to speak out of fear. In the meantime, Fleet develops a close friendship and budding puppy love with Claudette, Humphrey and Kate's daughter, who has organized a initially misfit team of her own to participate, with Humphrey as their coach.
This does not go unnoticed by Nars, who then further pressures Fleet to become antagonistic with her, seeing her as the enemy. His motivations are later revealed to have been instigated by losing the Wolf Games against Kate when they were pups, which resulted in a life-long self-hatred and aggressively competitive attitude. This extends to pushing the pups he coaches to cheat, even to an extent that could get the other competitors hurt (such as knocking rocks into the path). However, Fleet defies his father and, working alongside Claudette, finishes the final race of the Wolf Games in a manner where both he and Claudette tie. Enraged that he was deprived of a victory through his son, Nars is about to confront Fleet when he notices how happy his son is despite the loss. Realizing that Fleet could move on, Nars then decides to congratulate his son, gradually shedding his aggressive ways.
At first, Nars simply appears to be the stereotypical coach that becomes too invested in the competition (and is, to an extent). However, as the plot goes on, it becomes apparent that Nars' obsession with winning goes much further, to the point of pushing his son. Throughout the film, there are a great many hints that Nars emotionally abused Fleet by condemning him unless he met his approval. This abuse may have also been physical, as seen when Nars threatens to strike Fleet for speaking out against him, with the implication that it is far from the first time. His treatment of the other teammates, while not as explored as it is with Fleet, is suggested to be just as harsh, especially considering Magril's refusal to speak in his presence out of fear.
Going further, Nars also shows signs of mental illness when he emotionally breaks down a few times in the film when recalling how he lost. In these breakdowns, Nars begs his (presumably deceased) father to not be mad, and that it wasn't his fault that he lost to Kate. These breakdowns hint that Nars' own father might have also been quite abusive to him, providing a background for Nars' antagonism. This also extends to his irrational hatred of Kate, who has since moved on and barely even remembers Nars (although this element is mostly explored with Nars' attempts at making his son mistreat Claudette, essentially a form of revenge by proxy). Nevertheless, upon seeing his son technically not win and yet not be devastated by it, Nars shows signs of reforming himself.