The Lava Men inhabited Dino-Skeleton Island long before Uncle Monsterface found it. Whether or not the Lava Men are responsible for the construction of Uncle Monsterface's current lair, The Super Huge Treehouse Volcano, is unknown, but seems likely at least in part.
Information about the Lava Men began to surface one fateful evening in 2010. Following the departure of long-time Uncle Monsterface Chief Science Officer, Perfect Jimmy and the disappearance of Uncle Monsterface himself (in search of the Lost Sock Puppets), Marty and Paradise Dan set out to map un-explored areas of Dino-Skeleton Island (though some claim they were just "looking for a bar"). Meanwhile new recruit Spooki Olde Eric held down the proverbial and literal fort while trying to repair yet another ancient hover tank.
Nestled just north of the Beach of Childhood Regret, Dan and Marty made a discovery. The intrepid journeymen unearthed relics indicating that at some point the island had been inhabited by at least a medium-sized village. Crumbling foundations and curious oddments revealed themselves as Marty and Dan lost themselves excavating. They set up camp and set out to recover a piece of their history, and perhaps to find a new purpose for their team.
One fitful evening Marty was awakened by a sound coming from the nearby woods. He has at times claimed that it was both the voice of Perfect Jimmy and the voice of Uncle Monsterface himself (though it is known that Uncle Monsterface only speaks in "monster"). Regardless, the stray sounds lead Marty to a nearby grove, where he witnessed ,"a strange and flickering apparition," of Uncle Monsterface himself, beckoning him deeper into the woods. Curious but still wrapped in the fog of sleep and a pre-dawn mist, Marty ran after the evasive creature. He spotted it again poised atop a nearby hill, sprinted after it, and fell down a hole.
When he woke up, he could see nothing but blackness and the hole above him, now showering his blinking eyes with a beam of mid-day light. Luckily Paradise Dan's head was poking through that hole and lowering a rope down. As he landed on the floor of the cave and worried after Marty, he lit a torch.
The two young men were inside a giant cave. They looked up and were amazed at what the torchlight revealed. On the walls of this giant cave were painted countless primitive-yet-beautiful drawings, all detailing characters and actions that were heretofore alien to them, yet somehow felt familiar and close. The walls were covered with the tales of The Lava Men.
Now Uncle Monsterface (the band) has undertaken a project to decode these lost tales. While it must be noted that new paintings are still being found and studied amidstthis sprawling excavation, Team Monsterface has begun to formulate hypotheses based on their findings.
It is believed that, centuries ago, the island was inhabited by a population who worshipped and maintained the workings of The Lava Men. The Lava Men were iconic, super-powered beings "sworn to protect", each of whom held a sacred artifact, or totem, which summoned their powers forth. Actual members of the Lava Men were drawn from the human population of the island, a new Lava Man could be "called" if a current Lava Man was slain or retired by simply passing the artifact forward.
It seems likely that there were seven primary Lava Men, though it seems equally likely that there was a vast array of supporting Lava Men, known collectively as "The Rest".
The seven primary Lava Men were:
The Scuba Diver
The Brain Rocket Scientist
The Sports Robot
Along with an accompanying artifact, recent findings indicate that each primary Lava Man had an equally powerful "opposing" force or creature, as well as a native off-island location as their individual "home base."