Ruptga, also known as Tall Papa, is the chief god of the Yokudan pantheon. According to legend, he was formed around the time when the First Serpent shed its skin, creating Satakal. He learned the Walkabout, a way of avoiding the cycle of Satakal eating itself by moving in strange angles and striding between the worldskins. Ruptga placed stars in the sky to help other, weaker spirits perform the Walkabout, and it became so easy that it became a place, called The Far Shores.
Ruptga fathered so many children over the course of the cycles that he became known as Tall Papa. Most Prominent among his children are Frandar Hunding, Leki and Ansei. After many cycles, there were so many spirits that Tall Papa couldn't guide them all by himself anymore, so he created a helper out of the dead skins of previous worlds, called Sep. Sep still had much of the hunger of Satakal in him, and often ate the spirits he was supposed to help, though Tall Papa always got them out.
Sep eventually grew tired of helping Tall Papa and decided to trick the other spirits into creating a new world by balling up the remains of the old worlds, telling them that this new world would make it easier to get to the Far Shores. Tall Papa just shook his head at this.
Many of the spirits who pertook in creating Sep's new world died, and those who remained found that the jump to the Far Shores was too far now. They pleaded with Tall Papa for help, but he just told them that they must now find new ways to follow the stars to the Far Shores, or else live on through their children. Sep, however, required punishment, so Tall Papa squashed him with a stick. Sep is now stuck roaming Nirn while the other spirits can strive back for godhood, as a "non-space" that jealously tries to eat the stars Tall Papa has placed.