Thulsa was a simple creature, formed in the Lost World, in the village of Psamathe. He was driven... or distracted... by four main things: first, bopping dinosaurs over the head; second, eating extremely large portions of meat; third, experimenting with smoking or eating herbs; and last but not least, playing with very large, curvaceous Amazonian women who were forbidden to him... and extremely dangerous.

He was very strong and muscular. To a standard human, Thulsa was probably quite tall as well, but to an Amazon, he simply didn't have the edge. He was also driven by instinct. He was a master of survival when it came to foraging, fire, warmth, and even medicine...not through research, but because he had smoked or consumed nearly everything he could to experience it firsthand. His speech was very broken; he used the occasional word, along with plenty of hand gestures and pointing, mixed with grunts and sounds closer to those of a gorilla.

For all his simplicity and lack of knowledge about books or modern times, Thulsa was actually capable of summoning spells to aid him in battle. It was more of an instinctive defense mechanism, something that would burst out of him when needed. He was fairly safe around humans. He might point at them, prod them a bit, sniff them, or laugh at their voices, but he wasn't a threat...maybe clumsy enough to fall on someone, but nothing intentional. He was most often found in the mines, swallowing the souls of ape-like humanoids, whose loot and gold had saved him many times from an Amazonian sacrifice.