Maxwell "Max" Virum is Will, Kyle and Lucy's father, Nace's husband, Dib and Gaz's uncle and Professor Membrane's bodyguard. He is a former vampire hunter, ex-paranormal investigator, biker and a former marine force reacon operative who currently works as mercenary and private contractor empolyed by His-Tech industries. He is also a very skilled master in Bushido. He is also the wielder of the Doragon'nokiba, an unbreakable katana, given to his grandfather by a dying Japanese soldier during World War 2.
Max has pale skin, long past waist black hair and crystal blue eyes. His causal attire consists of black combat fatigues, black flack-jacket, and combat boots.
Unlike most characters in the series, Max is calm, sane and mentally stable. A skilled master in Bushido and Ninjutsu, Max is a stealthy and level-headed fighter. He is also one of the few adults to know Zim is an alien, but does not see him as an actual threat. As a parent, he shares his son's disgust with the way humanity is behaving twords itself and he stresses over his Will's future and education, stating that "this planet is no longer a place for a boy to grow up in".
- Max was inspired by Grey Fox and Raiden from the Metal Gear series, being a master swordsman and a stealthy figther.
- Max is shown to one of the smartest adults in the series as he know Zim's identity and is very disgusted with the way humanity has become.
- Unlike Professor Membrane, Max spends more time with his son and is very close to him.
- Much like Dib, Max was a paranormal invastigator. Though his motives greatly differ from his nephew's as he only searches for forces that definitely pose a threat.
- The name Virum means Bravery in Latin, symbolizing his strong willed nature and sense of bravery.
- His height is 5'10", weighs about 165 lbs and is 40 years old.
- He was also a father figure to his nephew Dib.
- The colors and design of his sword consist of a green and black hilt as well as a dragon across the edge of the blade. The holster also shares this design.
- The name of his sword, the "Doragon'nokiba" means "Dragon's fang" in Japanese.
- He is voiced by Jonathan Frakes, who played William T. Riker from Star Trek the Next Generation as well as voicing David Xanatos from the Gargoyles cartoon.