The Elementa Alliance was a cult founded by Sith lord Darth Dej. The cult was so named because the members were creatures who seemed to embody the elements of nature with the five leaders being: Metal, Fire, Water, Earth and Wind. Their ultimate goal was to summon the divine being Mentror.
The Elementa alliance began when Darth Dej discovered a crashed star cruiser. Slaughtering the surviving crew members he discovered a weathered parchment that had a list of the elements: Metal, Fire, Water, Earth, Wind, Ice, Lightning, and Plant. Also written was a way to gain ultimate power of the universe by way of summoning a divine being known as: Mentror. This was an artefact known as the Scroll of Mentror and was being transported to a museum before being hit by a meteorite and being knocked down to Technos. Thinking this to be a way to gain ultimate power Dej started up the cult and became founder and leader. Over the years he recruited other Sith to join him and they became known as lesser elements. Darth Flar was the first to join, motivated by promises of power and a large army at his disposal. Next came Darth Waw, inspired by the chance to dominate. She was followed by Darth Na who, like Waw, wanted absolute power. Finally there came Darth Grorg who was interested solely for revenge against his family whom he had believed betrayed him. Then there were the governors who were lesser still. They were one step below leaders and were charged with overseeing the people and armies. To summon Mentror, pure beings related to the element avatars must have been slain and had their blood poured into a goblet. The blood would then be poured into a hole in a shrine to Mentror and once all the blood was placed in the hole, Mentror would finally be re-awakened.
Finally after years of toiling and waiting the final goblet of blood was poured and Mentror could finally emerge. Sensing something to be wrong the Jedi sent a squad to investigate. They saw Mentror burst out from underneath the city and was leading an entire army of soldiers and vehicles. Shortly after recording the image and transmitting it however they were all destroyed by Mentror. Shocked and horrified the Jedi knew they couldn't defeat the Elementa alliance on their own and enlisted the help of the Imperial remnants. They were extremely reluctant and refused to fight alongside the Jedi until they realised that if Mentror and the Elementa alliance wasn't stopped then they to would be destroyed. The combined forces met up near Elem to discuss tactics.