The Pyramid of Atum is a building somewhere near the frontier town of Solstice. Ruled by Set, the pyramid is also home to Slave One and hundreds of other slaves.
History
After his last defeat at the hands of Sonic the Hedgehog, Set found himself trapped in the Ring of Eternity's limbo destination. Using his "genius", Set found his way to a "backwards rock" and enlisted slaves, presumably getting them to build the pyramid. He then set a plan into motion that would tear Tekno the Canary and Shortfuse the Cybernik from Mobius and bring them here.
With Shorty unconscious from a couple of intense beatings, Tekno was the only conscious prisoner in their cell and began to converse with the slaves guarding them. Soon enough, Tekno convinced them to set her free in exchange for her promising them freedom. As the slaves prepared to rebel, Set continued to search for the Eternity Ring. His plans ended when the rebellion began.
The slaves kept Slave One out of the way while Tekno forced Set into a rear chamber. After firing several shots from his staff, Set was crushed when the ceiling fell on top of him. Tekno then appeared to kill him with his own weapon. Tekno and Shorty left but returned to find the Eternity Ring. Two weeks later, with help from a scholarly slave, Tekno found the Ring's location. Before she left, she ordered the slaves not to enter Set's resting place. They disobeyed her, but found nothing.