Adas held the position of king over Korriban and the Sith, with his rule spanning nearly three centuries, or three hundred years. Notably tall for his species, he possessed an uncommon charcoal-colored skin tone and was groomed from an early age as a chosen one. He donned ebon armor, brandished a formidable battle-ax, and excelled as a master in the arts of Sith magic. Around 28,000 BBY, Adas brought together the scattered nations and tribes of Korriban through a sequence of violent confrontations, ultimately establishing himself as the singular leader of his people.
Adas was celebrated by the Sith as the Sith'ari, which translates to "Overlord." It was widely believed that he was invincible and his reign would last forever. Approximately in 27,700 BBY, Rakata individuals from the Infinite Empire made their way to Korriban, instructing Adas in the manipulation of holocrons. Adas constructed one of these devices, but soon discovered that the newcomers had intentions of conquering Korriban. He then confronted the aliens with his battle-ax, expelling them with the support of his people, but he was killed in the process.
Despite his death, Adas's influence persisted for many years. His holocron was later passed on to the Exiles in 6900 BBY, marking the beginning of the first Jen'ari, or "Dark Lord" of the Sith's reign. It was subsequently lost on Ashas Ree during the Great Hyperspace War, where it was eventually discovered by the fallen Jedi Knight Freedon Nadd, who utilized Adas's teachings to dominate and govern Onderon. In 4000 BBY, when that planet threw off the oppressive Sith yoke, the Jedi attempted to conceal the holocron to prevent it from falling into the wrong hands. It remained hidden on Kodai for almost four millennia before being recovered in the period leading up to the Clone Wars. Numerous murders were committed in efforts to seize control of the holocron, and it eventually found its way back to Korriban in the possession of Dark Lady of the Sith Lumiya.
Adas was a male Sith who originated from the planet of Korriban, existing at least three thousand years prior to the establishment of the Galactic Republic. His charcoal-colored skin, an anomaly among the typically red-skinned Sith, led to his designation as a chosen figure, resulting in a specialized upbringing from his youth. As he matured, he attained a considerable stature and demonstrated exceptional intelligence and combat abilities. Adas also proved remarkably skilled in the employment of Sith magic. He enveloped himself in spiked, ebon armor and wielded an oversized, alchemically-forged battle-ax. Around 28,000 BBY, Adas utilized his ax against his fellow Sith in a string of fierce battles, ultimately unifying and consolidating the disparate nations and tribes of his homeworld.
Through these actions, Adas ascended to become the undisputed ruler and king of Korriban. His people generally believed in his immortality and eternal reign, leading to his veneration as a deity. His rule became known as the "Reign of the Ax," and he acquired the title of Sith'ari, signifying "Lord" or "Overlord." At the age of three hundred, Rakatan soldiers from the Infinite Empire launched an offensive against Korriban. Initially, the aliens sought to gain the Sith ruler's trust by teaching King Adas how to preserve his essence within a "holocron." Adas applied this newfound knowledge to create his own holocron, although it served more as a record of his achievements than an instructional tool. Eventually, the Rakata's intentions became clearer as they attempted to conquer the Sith, utilizing their Force-based technology.
Adas assembled a substantial army on Korriban's fields to confront the invading Rakata, who landed their ships as the king's soldiers chanted his name. The Sith proved more than capable of defending themselves, and Adas, despite his advanced age, led his people in a vigorous defense of Korriban. He actively participated in the retaliatory efforts, driving back the invaders with his massive ax and eliminating numerous Rakatan warriors. He also captured Rakatan starships, turning them against the invaders. Adas's forces advanced from Korriban, reaching Ziost, Malachor V, and Tund. However, Adas died while striving to secure a future of freedom for his people. Around this time, a Sith named Yshaar Kael was labeled the "Betrayer of Adas" before being captured by the Rakata, and Raspir, Adas's court magician, was also captured and imprisoned in a mind prison.
In the absence of Adas's stabilizing leadership, Korriban once again descended into a state of constant civil conflict, with numerous individuals claiming the title of Sith'ari. Some Sith prophesied the eventual rise of a perfect being to assume the position of Sith'ari, while several Kissai priests maintained that Adas was the sole true Sith'ari, and that the prophecy began and ended with him. As a consequence of the internal turmoil, the Sith capital was relocated to Ziost. Details of Adas's exploits were subsequently documented by the Sith in the Holocron of King Nakgru. At some point, a mural depicting him was painted on the Mongrel Altar, a monument located on Korriban. Stability eventually returned to the Sith worlds, and a new Sith Empire was established, modeled after Adas's example of achieving power through strong individual leadership. Approximately twenty-one thousand years after his death, a group of Dark Jedi known as the Exiles landed on Korriban, subjugating the Sith people with their Force mastery and advanced technology, including lightsabers. Initially hailed as Jen'jidai, the Exiles destroyed Adas's eventual successor of that era and were subsequently perceived by the Sith people as gods, surpassing Adas in power. Ajunta Pall, the leader of the Exiles, was proclaimed the blood heir to Adas, and the Dark Jedi Sorzus Syn studied the accounts of Adas's reign detailed in the Nakgru Holocron. Upon his death, Adas entrusted his holocron to his second in command, or "Shadow Hand." The device was passed down through generations and eventually given to the newcomers, who were then celebrated as Sith Lords.
The Sith Empire flourished for many years until the Great Hyperspace War of 5000 BBY, when it was nearly destroyed by the Galactic Republic. During that conflict, Adas's holocron was lost on Ashas Ree by the Sith Lord Garu. In 4400 BBY, it was discovered by the fallen Jedi Freedon Nadd. Empowered by Adas's teachings, Nadd conquered and subjugated the planet Onderon. During the Beast Wars, the holocron came into the possession of Queen Amanoa, the wife of King Ommin, a descendant of Nadd. She too studied the ancient Sith's teachings and eventually passed the device on to her apprentice Novar. Novar, in turn, used the holocron to instruct further Onderonian Sith acolytes.
During her Jedi training with Jedi Master Thon, Nomi Sunrider learned from an ancient holocron which had been lent to Thon by Master Arca Jeth; the gatekeeper of the holocron was a Neti Master Ood Bnar. Master Bnar introduced Nomi Sunrider to the history of the Jedi's age-old fight against the dark side, including the reign of King Adas.
The decrees of the long-dead Sith king maintained an era of darkness on the planet until the Jedi broke the Sith's hold during the Second Battle of Onderon. The Jedi recovered the device and buried it under tons of water on Kodai, hoping to prevent anyone else from succumbing to Adas's influence. During the New Sith Wars, Brotherhood of Darkness member Seviss Vaa researched the Sith Empire's worlds and included Adas's reign in his writings. His research was later collected by Palpatine, also known as Darth Sidious, in the Telos Holocron, the contents of which were later published by Jedi Master Tionne Solusar in 40 ABY.
In 29 BBY, Norval, a student of Sith historian Murk Lundi, recovered the holocron. Subsequently, Jedi Knight Obi-Wan Kenobi confiscated the device and delivered it to the Jedi Council. The Council, in turn, entrusted Adas's holocron to the library of House Pelagia in the Tapani sector. In 19 BBY, a Jedi ExplorCorps member Telloti Cillmam'n discovered the armor of the Dark Jedi Warb Null on Nicht Ka, an ammonia-washed world situated on the edge of the ancient Sith Empire. Upon donning the armor, Cillmam'n experienced visions of ancient Sith history, including the Rakatan invasion of Korriban, where he witnessed King Adas's soldiers chanting their leader's name and Adas using his battle-ax to cut down numerous Rakatan warriors. Darth Sidious dispatched Carnor Jax's father, a Sun Guard, to retrieve Adas's holocron, but the man failed and was killed by the Sith Lord as a result. During the Great Jedi Purge that commenced in 19 BBY, Mecrosa Order agent Sir Nevil Tritum infiltrated the House Pelagia library. He killed three Jedi guarding the device and brought it back to his superiors. It eventually came into the possession of the Dark Lady Lumiya, who returned it to Korriban, where she resided for a period.
Adas was both a monarch and a deity to his people, and towards the end of his reign, he was bestowed with the title of Sith'ari—the perfect being, granted to him by the Force according to legend. A formidable combatant and a respected, albeit rigid, ruler, Adas remained feared millennia after his death. He exploited the timid, enslaved those he deemed foolish, executed idealists, and held the weak in contempt; his essence, preserved in a holocron, would refuse to impart its teachings to anyone it considered unworthy. While his holocron was generally reluctant to provide instruction, it possessed the unique ability to influence the minds of individuals in its presence when activated. Although initiates like Novar gained access to Adas's teachings, the Sith king's essence would threaten anyone who dared to fail him. When challenged by rival warriors, Adas would kill them and drink their bloodsoup, to honor their demise. He wielded a red-bladed Forcesaber and, during combat, brandished a pair of battle-axes, one in each hand.
Adas, in holocron form, made his initial appearance in a brief vignette within the 1996 sourcebook Tales of the Jedi Companion, authored by George R. Strayton. His role and biography were later expanded in 2006's Evil Never Dies: The Sith Dynasties, written by Abel G. Peña. This article identified Adas as a member of the Sith species and stated that he had interacted with the Rakata, who were introduced in the 2003 video game Star Wars: Knights of the Old Republic. Adas's character was further utilized and elaborated upon in 2007's Jedi vs. Sith: The Essential Guide to the Force by Ryder Windham.
In 2012, Adas was featured in the publication Book of Sith: Secrets from the Dark Side by Daniel Wallace, which expanded upon the details of Adas's legacy. The book included an image of Adas, resembling a previously unidentified darksider who had appeared in the 1994 comic Tales of the Jedi 5, in a flashback where the holocron gatekeeper Ood Bnar informed the prospective Jedi Nomi Sunrider about the dangers of the dark side, thereby retconning the comic as Adas's first appearance. In the Eternity Vault Operation, a group mission in the BioWare video game Star Wars: The Old Republic, a Sith Marauder named Yshaar Kael appears with the title "Betrayer of Adas," although the specific role Kael played in Adas's death remains unknown.
The 2014 article Authors of the Expanded Universe: More Tales of the Jedi, published in Star Wars Insider 151, described the dark-side user in Tales of the Jedi 5 as "an ancient Jedi who turned to the dark side."