He is one of the three majors of the Russian Army.
Maxim is a black and white German Shepherd dog, with various markings on his face. He has a dark muzzle and dark stripes under his eyes, he also has small spots over them. His face, chest, legs, belly and tail are coloured white. He has a lot of scars on his body, one being the bullet scar over his missing eye. He also has scars on his left cheek, left side of his chest, two on his right leg, and one on his back.
Maxim starts out as a ruthless soldier who has been raised to kill males, females, and puppies without mercy. However, he dislikes the killing of females and puppies and he is often shown to be against it. Still, as a soldier, he doesn't want to go against direct orders either. After meeting the Ōu Army, his sense of justice comes through and he begins to open up and make friends with the Ōu Army.
Maxim was trained as a war dog. He swam to Hokkaido from Russia together with Victor, Aram, Lydia, Bozlev and his pack in the hope of conquering the island as his own. Maxim is missing his left eye and has a gunshot wound above it thanks to the human soldier who shot him in the past.
During a fight with the island’s current leader Hakurō, Maxim kills off two of Hakurō’s sons Genbu and Byakko in an ambush. During the fight, Viktor goes after the escaping females and children, only to be stopped by Maxim who insists they kill the males first. After the battle is over and Hakurō is killed, Maxim refuses to stop Victor going after the survivors as he states its not his place to do so. Jerome is taken as a hostage and is greeted by Maxim upon awakening to be informed of the situation. Maxim orders Jerome to tell him about Ōu but the conversation is cut short when Ram is caught spying on them. Maxim gives chase but loses the collie among the bodies of Hakurō's pack. Maxim lets Ram go and heads back to Jerome and Lydia.
He helps his sister Lydia with healing Jerome and keep Victor from killing him, as he believes he needs him to scare Ōu into surrendering. While attending to the prisoner-of-war, Maxim meets Akame, whom he fights very shortly. Afterwards, when heading back to Victor, he gets surrounded by Victor’s brother Bozlev’s pack. After finding out who Bozlev is, he decides to take him to Victor. He is ordered by Victor to go with Aram to find the Ōu army’s base, but gets ambushed by Akame. Here, Maxim pretends to be wounded and runs back to Lydia to tell her of the Ōu army. However, he is betrayed when Victor and his pack surrounds and attacks him. He gets saved by Akame and taken to the Ōu army’s base. Afterwards, Maxim decided to go back and try to convince Aram to join the Ōu army as well. Lydia tries to stop him, but Maxim knows that Aram would be a good support as the battle against Victor would soon arrive.
Unfortunately, before they could fight Victor, Aram (who pretended to be willing to join Maxim) shows his true colours when he stood by to watch as Victor's minions tear Maxim to pieces. When he's down on the ground injured and unable to fight, Aram then jumps in and and rips his throat. He is then carried to the top of a cliff and thrown down to Gin's platoon, who have been captured by Victor. Maxim then passes out and was carried to the cave. Later on, while the Ōu army and the Russian Army Dogs were fighting hard in the gorge, Maxim had miraculously appeared out of the cave bloody yet determined to stop Victor from killing Gin but he was still unable to fight him. Fortunately, after the arrival of Weed and his reinforcements, he was also nursed back to health by the humans Daisuke Fujiwara and Hidetoshi Sekiguchi (who came to investigate the happenings at Hokkaido).
In the end, he swam back to his homeland to report to his father with his comrades Lev, Toli, Georgi, Sergei and Vasili while he left his sister behind with her new friends. However, a storm broke out and Maxim had nearly drowned from being washed by a bigger wave but when Aram's spirit aided him, he regained his courage to carry on swimming back to Russia. On arriving to the shore of Sakhalin Islands with Lev and Toly, he told his father that Hokkaidō is a barren land and they must carry on living in their homeland for survival.