In 9 ABY, Mok Shaiz, an Ithorian male, held the position of mayor in the city of Mos Espa, located on the planet Tatooine. Following Boba Fett's acquisition of Jabba the Hutt's criminal organization and his palace, conflict arose between Shaiz and Fett because Fett didn't provide the expected tribute. Instead, Fett anticipated that the Mayor would pay tribute to him. Subsequently, Fett faced an assassination attempt. The new crime lord then confronted Shaiz, suspecting his involvement. However, the Mayor denied the accusations and dismissed Fett's threats. The truth was that Shaiz had secretly offered Fett's territory on Tatooine to the Pyke Syndicate. Fennec Shand, a Master Assassin, assassinated him while he was in hiding alongside the other crime bosses of Mos Espa.

Mok Shaiz, an Ithorian of the male sex, presided as the mayor over the city of Mos Espa and the surrounding areas on the planet of Tatooine. Within Mos Espa, Shaiz had his base of operations in the city hall, where a Twi'lek majordomo, several guards, and a desk clerk were at his beck and call. He received visitors by appointment within his city hall chambers.
Following the passing of Jabba the Hutt, the crime lord, in 4 ABY, Bib Fortuna, his majordomo, assumed control amid the resulting power struggle. Subsequently, Mos Espa was divided among three crime families: the Trandoshans, the Aqualish, and the Klatooinians. Given Fortuna's diminished power compared to Jabba, he had to depend on shaky alliances, which included providing payments to Shaiz.
In 9 ABY, Boba Fett, the former bounty hunter, alongside Fennec Shand, a Master Assassin, killed Fortuna, taking over his palace. Unbeknownst to Fett, Shaiz had accepted a bribe from the Pyke Syndicate, promising them the territory Fett was claiming. As Fett aimed to reconstruct the Hutt's criminal empire as his own, collecting tributes from many who had previously served Jabba, Shaiz sent his majordomo to Fett's palace. While Fett and Shand anticipated Shaiz himself would arrive to pay tribute, the majordomo instead extended his employer's greetings, informing the new Daimyo that the Mayor was preoccupied with urgent matters and requesting Fett to pay tribute to Shaiz. Fett didn't offer any tribute to the Mayor but allowed the majordomo to leave unharmed. Before departing, the majordomo warned that Shaiz might react negatively to Fett's response, hinting at a potential future delegation.
After assassins from the Order of the Night Wind attacked Fett and Shand, they apprehended one, who claimed the Mayor had sent him. Subsequently, Fett and Shand brought the prisoner to the city hall, where the majordomo attempted to turn them away, claiming Shaiz was unavailable for the rest of the week. Despite this, Fett forced his way into the Mayor's quarters as the majordomo apologized to Shaiz.

The Mayor inquired about the identity of the unexpected visitor, though Fett doubted the Ithorian was unaware of who he was. Fett threw the Night Wind assassin to the ground before Shaiz, accusing the Mayor of orchestrating the attack. The majordomo insisted on the Mayor's innocence, but Shaiz silenced him, identifying the assassin's affiliation with the Night Wind. Although Fett interpreted the Mayor's comment as an admission, Shaiz subtly signaled one of his guards, who fatally shot the assassin. This action led to a standoff between Fett's forces and the Mayor's guards, but Shaiz proceeded by acknowledging the Night Wind's illegal status outside Hutt Space, thanking Fett for delivering the assassin.
As the majordomo offered Fett a reward at the Mayor's request, Fett declared he was no longer a bounty hunter, but Shaiz questioned this assertion. Fett insisted he would accept the payment in lieu of the tribute he had expected from Shaiz, warning that the Mayor only served at the Daimyo's discretion. Unfazed, Shaiz suggested Fett reconsider who was behind the Night Wind attack, claiming he lacked motive and served at Fett's pleasure, though the crime lord remained unconvinced. Offering advice as his tribute, along with the earlier payment, Shaiz suggested that managing a family was more complex than bounty hunting. When Fett questioned him, the Mayor advised the Daimyo to visit Madam Garsa Fwip's Sanctuary, where Fett discovered his position was challenged by the Hutts known as the Twins, a brother and sister who were cousins of Jabba.

Later, the Twins revealed that Shaiz had promised Tatooine to the Pyke Syndicate, a claim Fett doubted. The crime lord attempted to confront the Mayor at the city hall, but Shaiz had already left to join the Pykes, who had begun assembling their troops in Mos Espa. After Fett, aided by a gang of Mods, pursued Shaiz's majordomo as he tried to flee the city hall, the majordomo disclosed that Shaiz was gone. Fett and Shand captured and interrogated the Mayor's majordomo, but Shaiz himself was nowhere to be found, though the Mods were sent to search the streets of Mos Espa for him. Eventually, following the Pyke Syndicate's expansion on Tatooine, the majordomo suggested Shaiz had fled offworld, claiming it was a scheduled vacation.
In reality, the mayor had sought refuge with the Pykes in Mos Eisley, sheltering in the Desert Survey Office. Shaiz was conversing with the Pyke boss overseeing the Syndicate's operations on Tatooine when Cad Bane, a Duros, reported on Freetown's involvement. Shaiz questioned whether the Tusken Raider tribe Fett had joined would pose a problem, prompting the Pyke boss to admit the Syndicate had orchestrated their massacre and blamed it on a Nikto biker gang. Upon hearing this, Shaiz expressed frustration with the escalating events, mentioning the bombing of the Sanctuary earlier that night, and reiterated he had only agreed to "surgical strikes" that wouldn't destroy his city.

After the Syndicate's defeat at the Battle of Mos Espa, Shaiz sat with the heads of the Mos Espa crime families as the Pyke boss announced their withdrawal from Tatooine due to the unfavorable conditions for their spice trade. Shaiz began to argue that Tatooine was hospitable, only for the Pyke to silence him by asking if getting shot or eaten by a rancor was his idea of "hospitable." Shaiz paused with the others when they heard gunshots outside, and stood as everyone drew weapons in defense. Within seconds, sniper fire entered through the windows, killing the three dons and the pair of Pyke sentinels. Shaiz began hyperventilating, searching for an escape, when a cable loop descended from the ceiling and tightened around his neck. He struggled to remove the noose, but the cable pulled up, strangling him until his neck broke. Shaiz's body hung lifelessly in the office, leaving the trapped Pyke official frantically firing through the ceiling of a room filled with six corpses.

Although Mok Shaiz concealed his true allegiance, he insisted he had no motive against Fett, claiming to serve at the crime lord's pleasure, while his majordomo conveyed what he said was Shaiz's sincere welcome. However, the Mayor expected tribute from the crime lord rather than the other way around, and acted as if he didn't recognize Fett when they met. When Fett brought the captured Night Wind assassin with an accusation, the Mayor responded as if Fett was still a bounty hunter. One of the Twins described the Mayor as "spineless."
Mok Shaiz had dark green eyes and light skin.
Mok Shaiz utilized a translator collar that converted his Ithorese speech into Galactic Basic. The Mayor was usually seen wearing a long green garment decorated with gold.

Mok Shaiz is a character that was originally conceived for the television show The Book of Boba Fett. John Rosengrant, a performance artist, played Shaiz, who was also voiced by Robert Rodriguez, the co-showrunner and director, along with Dokk Strassi. He was initially showcased in the series' trailer on November 1, 2021, and later mentioned by name in the series' debut episode, "Chapter 1: Stranger in a Strange Land," which aired on Disney+ on December 29, 2021. Shaiz made his first on-screen appearance in the subsequent episode, "Chapter 2: The Tribes of Tatooine," which aired on January 5, 2022.
Anton Grandert created concept art depicting Shaiz's meeting with Fett in Chapter 2. The concept art portrays the Mayor slightly differently from his final version, featuring different attire and a beard.