The series stars Kelzad's Original Character, Kelzad, and Yeelon Mekyr, two Super Soldiers being developed in an A.A.H.W. facility. After a mysterious explosion from Yeelon's tube frees both of them, the two work to escape the facility they are in.
However, by the end of the first episode, Project 00X, the status quo completely changes and Kelzad eventually ends up teaming up with Zalmamdar to oppose a corrupted Yeelon.
REALM is particularly notable among other Madness Combat fan series for its great animation, interesting plot that not only adds a bit of lore to the Madness Combat series but also seemingly takes place in the same main series, and stellar soundtrack.
- Alien Blood: Kelzad and Yeelon both shed yellow blood, similar to A.T.P. Engineers and Soldats.
- All There in the Manual: REALM: Deterioration, a short written story, serves as a prequel to the series and explains the backstory of several characters. It also reveals Yeelon and Zalmamdar's original names.
- Anti-Villain: Zalmamdar borders on Hero Antagonist. REALM: Deterioration reveals that he was working against the Employers the entire time.
- Bash Brothers: Kelzad and Yeelon work together for a bit to fight off A.A.H.W. units. Kelzad and Zalmamdar also make a pretty good pair.
- Big Bad: Zalmamdar Oox in the first episode, but it soon becomes apparent that Yeelon Mekyr is the true threat.
- The Cameo: Kelzad and Yeelon catch sight of some events transpiring during Madness Combat 10 specifically the Auditor exploding during his battle with Hank and Sanford, after accidentally absorbing Tricky in Project 00X.
- Cliffhanger: REALM: Fraternization ends with Kelzad and Yeelon / Sokar facing each other.
- Cool Mask: Kelzad dons an A.T.P. Engineer mask in the first episode.
- Cyber Cyclops: When Kelzad gets revived, he gains a single green eyepiece.
- Demonic Possession: Yeelon appears to undergo being possessed throughout the first episode, given his sudden change in appearance and betrayal of Kelzad at the end of it.
- Elite Mooks: Kelzad at one point comes across a Sleepwalker Patient from Madness: Project Nexus who holds his own against him a lot better than the Agents.
- Enemy Mine: Kelzad teams up with Zalmamdar after recognizing Yeelon / Sokar as the greater threat.
- Evil Genius: Zalmamdar is a scientist and a member of the A.A.H.W., the villains of Madness Combat. However, REALM: Deterioration makes him out to be more of an Anti-Villain, so the "evil" part may be subverted.
- FaceHeel Turn: Yeelon turns on Kelzad at the end of Project 00X and cuts his scalp off.
- First-Episode Twist: Kelzad has an Improbability Drive in his head.
- From Nobody to Nightmare: Yeelon goes from a Supersoldier grunt to a dark god capable of warping reality.
- Greater-Scope Villain: The Auditor is mentioned a few times in REALM: Deterioration, but never actually appears in the series, aside from Kelzad and Yeelon witnessing him explode from afar. Deterioration also reveals that the Auditor is one of the Employers from Madness: Project Nexus 2, and that they have imprisoned the apparent Big Good of the series, the High. While they make a brief appearance at the beginning of REALM: Fraternization, they remain distant from the setting, though it's hinted they may have influenced some of the events in the series.
- I Have Many Names: Yeelon Mekyr, August Huffman, Sokar...
- L33t L1ng0: The first two titles: Project 00X and Project M3KYR.
- Made of Iron: Subverted by Yeelon and Kelzad in the first episode. Yeelon even injures his back from falling.
- Nightmare Face: Yeelon gains red eyes and a creepy grin after being overtaken.
- Night of the Living Mooks: Yeelon revives an army of agents and engineers, as well as Abominations from Project Nexus, to attack the Science Tower.
- One-Man Army: Kelzad and Yeelon manage to storm through the A.A.H.W. Mooks with little effort. Zalmamdar also does pretty good against Sokar's reanimated A.A.H.W. units.
- Reality Warper: Yeelon manages to change the color of the sky from red to purple.
- Shock and Awe: Kelzad wields two staffs that generate electric strands in REALM: Fraternization. He can also combine them together to create a bigger electric strand.
- Sinister Scythe: Sokar summons a scythe as he is facing Kelzad.
- Splash of Color: While red and yellow occasionally already appeared in Madness Combat, this series adds in purple and green to the mix.
- Took a Level in Badass: Kelzad is a much better fighter after his revival in REALM: Project M3KYR
- Villainous Rescue: Zalmamdar and several of his A.A.H.W. units save Kelzad when he is in the clutches of the Demon.