- Enhanced armor: The armor of the suit is capable of repeatedly taking blows from individuals with super-strength. At one point is had an entire building collapsed on itself and survived.
- Enhanced strength: The suit of the Justice Buster is capable of going toe-to-toe with invulnerable individuals although Batman doesn't predominately rely on it, instead using its specialized functions.
- Telescopic Fists:
The Justice Buster also had several mechanisms used to eliminate key Justice League members. Specifically:
- The Bind of Veils: Used to incapacitate Wonder Woman, the Bind of Veils is an ancient hellenistic relic created by the Olympian god Hephaestus in a moment of doubt after having created Diana's Lasso of Truth. It is an inverse of the Lasso's weave, made from the wool of the sheep that the legendary Greek hero Ulysses used to trick the cyclops Polyphemus on his odyssey. It is used to bind Wonder Woman in a delusional fantasy where she is successful over her enemy and frozen in victory as Bruce knows she never relents. He tracked the relic down on the supernatural black-market.
- Hyper-fast Servers: The servers of the Justice Buster are designed to process information and act faster than the Flash can run assuming he's not at optimal speed. It apparently required the most money of any part of the suit.
- Frictionless Fluid Cannon: Used to take out the Flash, the suit has a hyper-fast cannon that dispenses a frictionless fluid aimed at the Flash's feet. It is used to use his own velocity against him, causing him to crash at his own momentum while completely incapacitating him at the process. Thanks to the suit's servers, it fires faster than Batman's body can even react.
- Powdered Magnesium Carbonate Cannon: A cannon which fires a goop made of Powdered Magnesium Carbonate, a substance that rips moisture better than any other substance on Earth. It is used to defeat Aquaman by binding his body in the substance, preventing movement as the more he struggles the more it rips moisture from him.
- Electromagnetic Nerve Tree: A mechanism used to defeat Cyborg. It is presumably a mechanism which attacks at Cyborg's nerves with electromagnetic pulses, disorienting and incapacitating his mechanical functions.
- Citrine Neurolizer: A mechanism used to defeat the Green Lantern. Given that citrine is a yellow quarts and that a neurolizer is a fictional device from the film Men in Black used to alter brain physiology through flashing lights; it can be assumed that this device imprinted citrine lighting into Green Lantern's brain, preventing him from using his ring.
- The Red Giants: The knuckles of the Justice Buster have pods that contain red suns collected from dead solar systems and miniaturized by the Atom. Each knuckle has ten of these suns. Red Solar radiation is a weakness of Superman and as-such, the knuckles are highly effective against him.
- Plasma Shields: The suit has plasma shields which deflect heat-vision like that used by Superman.
- Thrust & Thermal: A mechanism used to counter-act Superman's freeze-breathe.
When the Joker used his virus to warp the brains of the Justice League as the beginning of his Endgame plot, Batman was forced to use the Fenrir protocol to eliminate his teammates. The suit was successful in eliminating Wonder Woman, the Flash and Aquaman but met an even match at the hands of Superman.
After a lengthy fight, Superman tore through the armor and nearly killed Batman until Bruce used Kryptonite chewing-gum to spit in Clark's face, rendering him unconscious.
- The Justice Buster is inspired by the Exoframe Batsuit from Batman: The Dark Knight Returns. This is even homaged when Batman punches Superman in the face, recreating an iconic from the original story.
- The name Fenrir is taken from Nordic mythology, in reference to the monstrous wolf of the same name. There can be multiple interpretations of Batman using this name. One is that it alludes to the suit being used to defeat gods as the Justice League is often compared to gods and Fenrir from myth is destined to kill several Norse Gods during the apocalyptic Ragnarok. Another is that is could allude to some variants of the Ragnarok story involving Fenrir killing the sun itself and Superman is the Last Son of Krypton. It could also more simple be a comparison of how unstoppable and monstrous the suit it.
- A mech based on the suit appeared in the LEGO set, 76117 Batman Mech vs. Poison Ivy Mech where it is referred to as the, "Batman Mech".