The Arrival

The tensions between the Atlantean sects had grown too tense to remain peaceful. Every side knew that, if things remained unchecked, the Priests and Warriors would go to war, destroying the Builders and the rest of the empire with them. The sides had come to conflict before and it had nearly destroyed them, so they could not allow such a thing to happen again. In a move that would save the Atlanteans, but not Atlantis, God-King Ra launched a deception that would have ramifications greater than any their civilization had ever seen.
The Atlanteans were masters of their own planet and as such had begun to expand to other worlds to make their own. On the supposed premise of growing their empire throughout the solar system, Ra had many of the greatest builders terraform Mars and Venus. Though each planet was different, they needed to be more suited to Atlanteans. Where once there was desert, there may be forest. Where once acid rain had eroded away at the cliffsides, now was refreshing snow. However, that is not all they changed. Mars and Venus had species on them already, like the chiktik and chaa'ri respectively, but they created and cultivated other species to make their own lives easier, much as they had done with the Vril-ya, and as such, the planets became vibrant and teeming with life.
The Warrior's found themselves on Mars, the Priests on Venus, and the Builders on Earth. Each was content and as the gates between their worlds stayed open, they were able to travel as they please. However, Ra and the few in his inner circle knew of what was to come. Though he had established these expansions under the guise of helping ease tensions, he had no intention of allowing these communities to grow on their own. He knew that even separate, as long as the Warriors and Priests could reach each other, there would still be conflict and war, and he was no interested in ruling over the ashes. As such, he severed the gates between their worlds, leaving Venus, Earth and Mars separated. The Priests and Warriors were caught completely off guard, as were the majority of the Builders. As panic set in on the foreign worlds, unrest began to build on Earth. The Builders, different as they were from the others, had friends, comrades, even lovers amongst the lost. More than that, even with their differences, they were still Atlanteans, much like themselves, and deception and betrayal was too much for them to handle. However, there was a second reason behind Ra's betrayal. Though it was true that the sects would most likely come to conflict due to their differences, that is not what drove Ra to his great schism. What drove Ra was that left unchecked, these planets might flourish while no longer under his rule and might challenge him for the seat of power for all of Atlantis. Leaving no option to chance, Ra cut them off, leaving them to perish on the prison's they had built for them, all while the rot of Atlantis remained on Earth.
It did not take long for the unrest in Atlantis to begin to boil over. First in whispers, then in clandestine meetings, before long it was neighbor against neighbor and brother against brother. A resistance formed by great leaders like Ganesh, Hera, Taud, and even the crowned prince Eduard began to combat Ra and his inner circle. Though many builders stood with the resistance, the acting military had been decimated by the loss of the warriors and those who remained were loyal to the crown. Suddenly, one day the entire royal palace had disappeared, a crater was all that remained where it once stood. The Resistance did not know what happened, whether is was some magical ritual done out of desperation gone wrong, a separate resistance cell who was determined to win at any cost, or something else entirely, all they knew for certain was that the palace was gone and along with it Ra. The royal remnants remained, but with the loss of their leader, the civil war was soon over. All that remained was to pick up the pieces, though it soon became apparent that it was a Pyrrhic victory. The remaining Builders could not recover their losses without the Priests and the Builders for their own numbers were so little. With little left, those who could left their physical bodies behind and bound their souls. The others became nothing more than memories and shadows. In a turn of fate, it was the builders that perished as a result of severing the ties between the castes. Though Mars and the Warriors would face their own troubles in time, the Priests would face no troubles greater than on the day that the royal palace of Atlantis mysteriously appeared on the surface of Venus.
The Priests entered the palace, finding it damaged from the war, but seemingly untouched by whatever event had brought the full palace here. The exception to this would be the dozens upon dozens of bodies that covered the floor. They could find no wound, no signs of illness on their bodies. Their faces even show no emotion besides peaceful repose. This is perhaps why they were caught so off guard when the first words emerged from the royal chamber,
"Approach"
Their feet began to take them into the chamber, no matter how much they resisted. Even the strongest will among them could not disobey his command. For that reason, they knew what awaited them long before he came into view, though they were taken aback, not by who they were expecting, but rather how he looked.
The once strong, statuesque Ra sat upon his throne drained of all his once magnificent strength. HIs skin gray and stretched, his ribs visible under his shrunken form, and most disturbingly his eyes, sunken into such blackness that they could hardly be seen.
"Kneel"
Their bodies betrayed their spirits as they found themselves submitting to this ruined God-King. With another word that boomed through the hall, one of the Priests found himself ripped off the floor and approaching the throne.
"Do not fret, this is your purpose and you could serve not one greater"
As Ra's fingers wrapped around the Priests throat, the others watched, unable to move, as the Priest was lifted up to the gaping maw of the God-King. Ra's body began to grow stronger, his features more defined as the screams of the priest echoed through the palace. His lifeless body hit the ground as Ra stood from his throne. Though he still bore the scars of whatever had brought him and the palace to this planet, his newfound strength gave him the authority to stand over his newfound subjects.
And with that, his new reign began. The Priests soon found themselves subject to his whims, a perversion of what they once were. Over the centuries the palace was transformed, and millennia later Ra sat at the center of The Tower of Souls. Though he grew no older, no weaker, he once again felt the stagnancy of his empire, knowing he must expand. With that, he began to watch through the crystals into the kingdom's that remained on Earth and Mars, waiting for the appropriate time. He did not know when or where his opportunity would arise, but his reach was boundless and nothing and nobody would stop him.