Arch-nemesis - The Adventurer
A huge, hairy Neanderthal caveman, usually wearing an expensive suit, but stripping to a loincloth for any serious combat that he has time to prepare for. His powers are virtually identical to those of The Adventurer, except that he is far older and almost completely amoral.
The Neanderthal has no other name, but sometimes assumes temporary aliases to carry out his plans. He is the last surviving representative of Homo Sapiens chief evolutionary rival and carries a grudge against all of humanity. He found his way to the fountain in prehistoric times and had a completely different reaction to the death of the Syntrivani. He would likely have glutted himself in an effort to wipe out the entire tribe had they not poisoned him with a substance that that caused him to fall into a deep sleep. He awoke later with no memory of the Fountain’s location. He has been trying to find his way back to take revenge ever since, and he knows that the Adventurer has the location.
The Neanderthal is a vicious brute who fights like a rampaging beast slashing with near indestructible fingernails and biting with intent to devour. He has no compunctions about killing when it serves his purpose, but is smart enough to know that a trail of bodies would be detrimental to his plans.
It seems that the Vigor of the Syntrivani reacts oddly when pitted against itself for both the Neanderthal and the Adventurer take significantly longer to heal when they fight each other directly. This has led both men to believe that it is possible for them to kill one another, a fact which the Neanderthal does not care for much at all. For that reason the villain will seek to come at his enemy indirectly as often as possible despite the fact that he has won several of their physical confrontations over the years. If anything this makes him even more dangerous as his cunning and evil mind is easily the equal of his vicious and beastial body.