Nolaa Tarkona, a Twi'lek female, held the position of leader within the Diversity Alliance. Distinguishing features included sharpened teeth and the absence of one lek, compensated by an ocular implant providing her with rear vision.
During the Imperial Era, Nolaa Tarkona was born on Ryloth. Like numerous other alien species, she experienced the effects of the Humanocentric policies implemented by the Galactic Empire's New Order, which intensified her hatred towards Humans. Furthermore, the Empire had enslaved a significant number of Twi'leks, and her half-sister, Oola, met her demise as a slave in the palace of Jabba Desilijic Tiure when he offered her as food to his rancor pet.
Determined to avoid a similar destiny to that of her half-sister, Nolaa, who was enslaved, rebelled against her captors and initiated an uprising, which ultimately led to the overthrow of the Ryloth government. Subsequently, Tarkona achieved the distinction of becoming the first female Twi'lek leader in galactic history. Twi'leks who did not adhere to Tarkona's principles faced execution, exile, or forced labor in the ryll mines.
Shortly thereafter, Nolaa established the Diversity Alliance, utilizing the profits from Ryloth's ryll to finance her endeavors, and disseminated her message of alien solidarity to various species throughout the galaxy. She organized numerous rallies on different alien planets, garnering support for the Alliance. Many aliens joined her, including Wookiees, Quarren, Ugnaughts, Trandoshans, Duros, and Chironians. While the Diversity Alliance appeared to be a peaceful movement prioritizing aliens on the surface, Nolaa conceived it as a means for all non-humans to unite against a mutual adversary: Humans.
In 24 ABY, an alien scavenger by the name of Fonterrat made a discovery of the Emperor's plague storehouse in the Deep Core. This hidden location contained a collection of lethal diseases created by General Evir Derricote nearly two decades prior. Despite the defeat of the Galactic Empire, this plague warehouse and its stockpile of deadly diseases remained intact. Aware of Nolaa's animosity towards Humans, Fonterrat proposed selling her a navicomputer module containing the storehouse's coordinates, but he declined to engage with her directly, suggesting that she dispatch a neutral party to meet him on Kuar.
During the negotiation, he also gave her two virus samples, one of which she used to ensure his payment. (She used the other on the last of the Imperial Royal Guards as a demonstration for Rullak, Corrsk, and Kambrea.) The neutral party turned out to be Bornan Thul, a wealthy Human merchant and shipping magnate. Bornan paid with a time-locked case filled with credits in exchange for the navicomputer module, which contained the coordinates for the asteroid.
Bornan was then scheduled to deliver it to Tarkona at a trade conference on Shumavar, but he discovered the contents of the plague warehouse and went into hiding. Infuriated, Nolaa enlisted numerous bounty hunters to locate Thul and retrieve the navicomputer. Among these bounty hunters was Ailyn Vel, disguised as her father Boba Fett.
Later on, Raynar Thul, Bornan's son (who was a student at Master Luke Skywalker's Jedi Praxeum on Yavin 4), sought out his father with the assistance of his classmates Jacen Solo, Jaina Solo, Tenel Ka Djo, and the Wookiee Lowbacca. Their search led them to his last known locations, encompassing ancient ruined worlds such as Ziost and the droid foundry world of Mechis III.
Fonterrat also traveled to Gammalin, an all-Human colony, where he unknowingly unleashed the plague, resulting in the annihilation of the population. Prior to the plague taking effect, Fonterrat was imprisoned by the colonists. As the plague had eliminated everyone on the colony except for Fonterrat, he succumbed to starvation in his cell, as there was no one to care for him. Meanwhile, Nolaa Tarkona persisted in her mission to rally support among the alien species of the galaxy, visiting the Chromans of Chroma Zed, where she recounted the oppression under the Empire.
Subsequently, Lowbacca was recruited into the Alliance by Raabakyysh, a female Wookiee, and journeyed to their headquarters on Ryloth to gain deeper insights into their organization. Simultaneously, Zekk, a Human friend of the Jedi, rescued Bornan from bounty hunters and discovered the reason for his disappearance, as well as the existence of the top-secret Imperial plague warehouse. Bornan also disclosed that Boba Fett (actually Ailyn Vel) had infiltrated his ship's navicomputer and obtained the coordinates of the plague warehouse. Ailyn Vel then presented this information to Nolaa, who intended to release a Human-specific plague upon the galaxy.
Sensing that Lowbacca was only aware of the public image of the Diversity Alliance and not the underlying anti-Human sentiment, Lowie's Jedi companions traveled to Ryloth, only to be apprehended by local authorities and forced to work in the perilous ryll mines of Ryloth. However, Lowbacca soon learned of the fate of his Human companions through Raabakyysh.
The enraged Wookiee turned against the Diversity Alliance and aided them in escaping the harsh terrain of the planet and the zealous Diversity Alliance troops. The Jedi also discovered that the Diversity Alliance was holding Humans as slaves in its ryll mines and amassing weapons for its war against Humans. They were also rescued by Zekk, Luke Skywalker, and Lusa (a Chironian who had abandoned the Diversity Alliance due to the death of her Talz friend and disillusionment over executing an operation). The Jedi then fled offworld to the galactic capital of Coruscant.
This event garnered widespread attention throughout the galaxy, leading to a special session at the New Republic Senate to address the issue. There, in front of thousands of Senators and representatives, Luke requested that an inspection team be dispatched to Ryloth to investigate reports of Diversity Alliance aggression. Upon learning of this, Nolaa Tarkona instructed Kambrea, a trusted Devaronian friend, to entertain the inspection team and conceal any evidence of Alliance aggression. She also prepared a fleet to head to the plague warehouse.
Meanwhile, on the Jedi/New Republic side, after recording an encrypted message to his wife Aryn Dro Thul explaining their plan, Bornan, along with Raynar, Zekk, Jacen and Jaina Solo, Tenel Ka, and Lowbacca gathered explosives and journeyed to the warehouse with the intention of destroying it. They were nearly finished wiring when Diversity Alliance ships arrived. During the ensuing confrontation with Tarkona in the warehouse, some of the plague canisters were broken open, including Human and Twi'lek specific virus. Bornan sacrificed himself to prevent the plague from spreading, instructing Raynar to evacuate himself and his friends from the asteroid.
Simultaneously in space, a New Republic fleet under Han Solo defeated the Diversity Alliance fleet. On Ryloth, fighting erupted when the New Republic inspection team uncovered stockpiles of weapons. However, the fighting was brought to a halt by Kur, a Twi'lek who convinced the Alliance soldiers that they had been misled and that both Humans and Aliens should collaborate.
As the Diversity Alliance faced defeat, Nolaa and Raaba fled to an uncharted world in the Outer Rim aboard their transport Rising Star, where Nolaa succumbed to a slow-acting disease that ravaged her body by destroying her immune system and causing excessive sweating. She had attempted to persuade Raaba to take her to Coruscant so she could infect her enemies, but she failed because the Wookiee had become disenchanted of the Alliance's ideals by then. This marked the end of the Diversity Alliance, which disintegrated upon Nolaa's death.