He is an average man who is practically bald, presumably because of the extreme amount of stress from being cruelly abused by Yunju as well as the constant impending doom of being executed by the latter. He also wore no clothes, with only a collar and leash around his neck, as per the Chimera Ant's will. Much like Spot, his tears never stopped in his appearances.
With his mind, body, and spirit were broken by being "tamed" by Yunju, he and Spot acted like a 'human-dog' and was constantly fearful and terrified for his life. Together, they did everything in their power to try and survive under the cruel reign of Yunju, no matter how pitiful it was.
He was one of Gyro's men until being made into a pet by Yunju.
Chimera Ant arc
After Yunju's team attack the hidden D² Manufacturing Plant in NGL, Spot and him are made human-dogs by the Chimera Ant Squadron Leader. When Kite, Gon and Killua arrive at the plant, Spot begs for help. Yunju intervenes by killing Spot and then decides to kill Rover as well. Not wanting to be killed, Rover attempts to act like a dog in hopes of pleasing the cruel Chimera Ant, but doing so only has made Yunju want to kill him even more. Before dying, Rover screams for help to Kite and company and is immediately killed right after.
Translations around the World