Near the end of the battle, Sirrek and Mac confronted Werth Plouth, the Path's Herald and the Children of the Open Hand, a subgroup of the Path, successfully defeating them despite their use of the living weapon known as the Leveler and getting Plouth arrested. Sirrek formed a strong kinship with Mac due to the experience, and the two shared their beliefs that the Path had been behind the bombing and the artifacts going missing. In the aftermath of the battle, Sirrek was given a seat on the Convocation of the Force, a council of religious groups, where he independently represented those without affiliation to said groups.
Tey Sirrek was a Sephi male who joined the Guardians of the Whills as a member. In 387 BBY, Sirrek was stationed as a guard at the Temple of the Kyber. While on duty, he caught a young Cragmoloid Flim pickpocketing from a passing civilian with the help of a small droid SK-0T. Sirrek quickly left his station, chasing after Flim; however, he failed and lost the small thief. During a training session with other guardians, Sirrek brought up the name he had heard from the thieves, Anst Wozo, to Captain Oklane Viss. Viss initially dodged the question, though he later told Sirrek that Wozo is "bad news."
Sometime later, Sirrek caught onto Flim but was stopped as Wozo approached the two. Before Sirrek could do anything, he was called back by Viss and left. The next day, SK-0T showed up for help and Sirrek immediately rushed after the droid. SK-0T guided the Sephi to a room full of unconscious children, including Flim. Viss who followed Sirrek ensured that the kids were still alive. Sirrek checked on the young Cragmoloid, though he did not make it. Sirrek confronted Viss about the cause of it but the captain refused to answer, telling him that it was not their responsibility. In anger, Sirrek followed and attacked Wozo, killing him.
Later he considered himself a defender of the oppressed and was a skilled thief. In 382 BBY, Sirrek discovered that there had been robberies of artifacts all over the Holy City of the Pilgrim Moon Jedha. He arranged a meeting in the Wayfarer Quarter of the Shrine of Sarrav with a Sarravi woman named V'Kara who had information about the robberies, but was not listened to by the groups she went to with her information.
Before the planned time of the meeting, Sirrek went to the Jedha marketplace where Ran Yaltan, who claimed to be the last of the Truthsayers of Bpfassh was putting on a show. A member of the crowd claimed that Yaltan was a fraud, but Sirrek went to calm them, telling them that they shouldn't be unpleasant right before the Festival of Balance. When asked, Sirrek told them that the Convocation of the Force announced it, but the individual said that the Convocation didn't have a right to force their celebration upon them. Then Jedi Padawan Matthea Cathley inserted herself into the conversation, giving Sirrek the opportunity to steal an object from the annoyed individual. However, Jedi Master Vildar Mac, who was with Cathley, spotted Serrik steal and chased after him, but Sirrek managed to elude the Jedi.
Sirrek then went to the Shrine of Sarrav to meet with V'Kara, but discovered her dead on the shrine's floor. Master Mac spotted Serrik in the shrine and recognized him as the thief from earlier, immediately jumping to the conclusion that Sirrek had killed her and swung his lightsaber at him. Sirrek dodged all of Mac's strikes easily to the Jedi's bewilderment, Sirrek claiming that he could do so because he had mastered many Force powers, including Vitali, Cry of the Broken King, and Morichro. Mac claimed that Morichro was a myth, but Sirrek placed his hand on Mac's chest and stopped his heart, claiming that he had used the technique. In reality, Sirrek had just used a pheromone his ancestor's had developed that temporarily knocked people down.
After Mac came to, the Jedi used a unique Force ability to track Sirrek to Enlightenment, a bar in the city. Mac spotted Sirrek going to leave and threw a knife into his cloak that halted his movement. Mac claimed to the bar's owner, Kradon Minst, that Sirrek was a dark side user who had used Morichro, but after Mac described the ability, Minst turned to Sirrek and asked if he should tell the Jedi or allow him to. After ripping his cloak to get free, Sirrek introduced himself to Mac, claiming he was a righter of wrongs, with Minst adding that he was a Sephi. When Mac claimed Sirrek was a murderer, Sirrek showed him a hologram recording that his droid projected and explained that he had discovered her dead and was really going to meet with her about missing artifacts. He also explained that he had used no magic against Mac and explained the special pheromone. He then gave Minst extra credits for his trouble and left, ignoring Padawan Cathley's suggestions at working together.
Sirrek then met with a Condluran named Briff, knowing that Briff bought special items. Sirrek then offered Vildar Mac's lightsaber, which he had stolen from the Jedi in Enlightenment, though the Condluran turned it down. Sirrek then spotted a statue of a starbird made out of kyber crystal in one of Briff's crates and picked it up. Briff held a blaster to him, but then Master Mac jumped down from above and disarmed Briff, but they had another blaster in their other sleeve and shot at the Jedi. Sirrek jumped in the way of the bolt, though was not hurt due to his body armor. After Briff took off in a speeder, Mac noticed that Sirrek had saved him, but Sirrek thought it was ironic considering Mac was meant to be aligned with the Force. Mac also said that stealing from a Jedi took audacity, and that he was almost impressed by Sirrek. Cathley commented that they had lost their only lead, and Sirrek confirmed that he had been trying to find out who was in the market for stolen artifacts. He told them that he knew where the statue of the starbird was from, saying that if they had thought stealing lightsabers was hard, it was a much bigger deal entirely.
Tey Sirrek first appeared in the first issue of the 2022 comic series Star Wars: The High Republic published as part of the Star Wars: The High Republic multimedia project's Phase II. The issue was written by Cavan Scott, and published by Marvel Comics on October 12, 2022. On May 26 of that year at Celebration Anaheim, Scott first indirectly mentioned him as part of the then-upcoming comic series. Tey Sirrek was first identified by name in a StarWars.com post on September 22, 2022.
At Celebration Europe the following year, Scott expressed his thoughts on the then-ongoing comic issues Sirrek and Mac featured in. The author indicated that the latter half of the series would show the two growing closer together during their trials on Jedha, confirming for an interviewer that their relationship would further their bromance with a bit of romance. This aspect was later evidenced by the issues released after Scott's interview, culminating in a kiss both share in The High Republic (2023) 6.