Back in the days of Outworld where the entire realm was under the rule of the Dragon King, Saishi was an Outworlder civilian who had managed to steer clear of the wars that sparked during Onaga's attacks on those who opposed his goal of ruling the entire realm which previously had been split into five groups; the Outworlder humans, the Tarkatans, the Centaurs, the Shokan and the Dragons. The Dragons had seemingly all been slaughtered by Onaga himself for reasons unknown to the general public… but the fact he had caused such a genocide on his own race was wellknown nonetheless.
The rulers of each respective civilisation made their own decisions regarding how they responded to Onaga's declaration of rulership, with the ruler of the Outworld native humans refusing to obey anybody… leading to their swift but painful death. This refusal led to a war and was a sign that nobody should dare oppose the one true ruler of Outworld. Saishi had evaded this war, despite of course being part of the Outworlder civilization, and this was because of his nature to explore. His occupation was that of a hunter for exotic beasts that lurked throughout the realm. He left home for a while and became a wanderer briefly, soon returning home once Onaga had asserted full dominance and nobody was left to challenge him. Saishi still wasn't safe though, as many years later Shao Kahn would use acts of cowardice in order to slay the Dragon King and take his place as Emperor. It was now Shao Kahn's turn to assert his dominance over the realm, with his extermination squads threatening civilians into pledging their loyalty to the new rulership, as well as hunting down any remaining allies of Onaga.
A small group of loyalists were located in Saishi's village… one so old that he could no longer recall its name… and the conflict led to a fire which set fire to Saishi's home and soon spreaded across the entire small village and burnt everything to the ground. Saishi was severely injured from several burns of varying degrees, but he survived. Saishi returned to his lifestyle of a wanderer after he had recovered from his injuries, hunting to survive as he moved into the Golden Desert which was the largest desert in the entire realm. After the fires he was a victim to and the heat of the desert, Saishi had adapted to the warmth and cared for it no longer as he had adapted to the lifestyle and moved to Mt. Eterna, a volcanic region neighbouring the Golden Desert that was the hottest location in all of Outworld. Because of the heat and danger of all the deadly lava, this area was completely uninhabited… perfect for Saishi's new home.
Saishi would continue to venture to and from the Golden Desert for food and valuables, and one day he wandered to the Sarna Ruins. Due to how used he was to extreme environments, he cared not for the violent tornadoes that dominated this area of the Golden Desert. There he found the Lost Tomb of the Dragon King, and the last of his Holy People. Considering the fact he fared better during the rule of Onaga paired with his hatred for Shao Kahn after the destruction of his village and his permanent burn scars, Saishi didn't hesitate to agree to help the group of Onaga loyalists and showed them his home in Mt. Eterna where the Lava Shrine would be born to protect the Great Dragon Egg which was in danger at the Lost Tomb due to the nearby natural disasters.
The Lava Shrine was within a hollowed out part of a volcano which had been inactive for countless years. Saishi was immediately granted a place within the group of Holy People, soon gaining a new title of the Lava Shrine Priests thanks to Saishi revealing a suitable location for the Great Dragon Egg. Saishi was still the most unique of the group though, wielding his large trusty axe he used for hunting that he refused to part with despite the fact the Lava Shrine Priests prioritised their newfound sorcery over weaponry, sorcery which Saishi soon learnt as well thanks to Onaga sharing a gift of power replication that was a weaker form than the one he'd later give to an Earthrealmer boy named Shujinko, as it only allowed the Lava Shrine Priests to replicate a single power which for them was lava manipulation which by extension also granted fire powers. Saishi would practice his magical powers extensively to become a master fire and lava bender.
Saishi will continue to aid his allies with their survival and to help them with restoring the one true ruler of Outworld to return the realm to its former glory which for Saishi was a much happier time for the old lone wanderer who was alone no longer. Long live the Dragon King Onaga!