Warmonger is the chief general working for Skullmaster. He is a brutish-looking humanoid creature with horns and dreadlocks who is armed to the teeth.
He debuted in Mighty Max Battles the Skull Master on Skull Mountain wherein he was an orange-colored figure with red horns, a blue loincloth and silver-painted weapons on his hands. In the accompanying comic, Warmonger attempts to stop Mighty Max from escaping Skull Mountain. Skullmaster, in an attempt to kill Max, launches the Doom Stone, but it hits Warmonger instead and apparently kills him.
Warmonger appeared in the TV series later, although this time he was colored red instead of orange. Speaking with a thin, raspy voice seemingly not befitting his hulkish appearance, Warmonger commanded Skullmaster's legions of Rock Monsters and Lava Beasts. Because they were trapped at the center of the Earth, Warmonger was, generally, little more than a slave driver, keeping the enslaved Lava Beasts in line. But after the reappearance of Lava Lord, Warmonger escaped to the surface with Skullmaster and got to play a somewhat more active role as Skullmaster's sidekick and henchman.
In particular, when Skullmaster wanted to seize control of Hydra so as to upset the balance between good and evil, Warmonger stole the page from the Lemurian Arcana that would've let Skullmaster control Hydea. Instead, Warmonger now controlled the beast and turned on his master, commanding Hydra to kill Skullmaster, which he (apparently) did. Warmonger then went on a destructive rampage with Hydra until he was stopped when the Mighty One restored the balance. A dejected Warmonger returned to Skullmaster's lair...where he found Skullmaster alive and well. Skullmaster explained that he had known Warmonger would betray him and had engineered his fake death in order to force Virgil to use a vital page from the Lemurian Arcana against Hydra, instead of him.
When Skullmaster re-forged the Crystal of Souls, he asked if Warmonger were loyal enough to give up his soul to it. Warmonger worriedly refused, prompting Skullmaster to mention he had "other plans" for his underling. Those other plans were revealed once they arrived at Stonehenge. Initially, Skullmaster had Warmonger restrain Max after killing Virgil, so Max could witness his final victory. However when Warmonger spoke up and asked what he was going to get out of all of this, Skullmaster used the Crystal of Souls to zap Warmonger, killing him.
It is never stated but because time is reversed during Max and Skullmaster's final battle, Warmonger probably came back to life as well and is re-trapped in the center of the world with Skullmaster.