"Any archer who wears the yuyan tattoo can do that, your Highness. I can pin that fly to that tree a hundred yards away without killing it ... and I can do it blindfolded."
— Vachir bragging about his skills to PrinceOzai.
Vachir was a dishonored Yuyan Archer who was forced to resign from the elite force after failing then-PrinceOzai. Following these events, he became a member of the Rough Rhinos, where he served as their bowman. He specialized in fire arrows and his bow had a small torch just below the grip to ignite them. Vachir, along with the rest of the Rough Rhinos, was responsible for the deaths of Jet's parents and the destruction of their village.
As a young boy, Vachir attended a Fire Nation school, where he was a star pupil under Ms. Kwan. He was taught discipline and hard work, which would help him in his later life.
As an esteemed member of the Yuyan Archers, Vachir was called to the Fire Nation Royal Palace by Prince Ozai, where he received the mission to travel to Hira'a and assassinate Ikem. Confident in his skills, Vachir accepted and left immediately. Many months later, the Yuyan Archer returned to the Fire Nation's palace to report to the prince that he had failed to locate and kill Ikem. Based on report of the local residents of the town, Vachir had traveled inside the Forgetful Valley and searched for Ikem, albeit with no success. Vachir concluded that no commoner like Ikem could have survived in the hostile environment and returned home. However, Prince Ozai was not pleased with his findings and commanded Vachir to return to Pohuai Stronghold to hand in his resignation to Colonel Shinu, stating that since he failed to complete Ozai's request, Vachir no longer qualified as an elite fighter, the best of the best.
Vachir did what he was told by the prince and left the Yuyan Archers, though he kept his equipment and uniform. Sometime later, he became a part of the Rough Rhinos, and as their resident archer, he and the rest of the group attacked the village where Jet and his family lived around 91 ASC. In their attack, they killed his parents and destroyed the village, leaving Jet with a hatred of the Fire Nation for years to come. In late 99 ASC, Vachir and his comrades invaded another Earth Kingdom village, forcing several inhabitants to become refugees; among these were Tahn and his pregnant wife, Ying.
Vachir first encountered Team Avatar with the Rough Rhinos in 100 ASC at a small village; never having met Aang before, he and the Rhinos believed Sokka to be the Avatar and apprehended him instead of their true target. Even so, Aang, Katara, and Toph used their abilities to ward of Vachir and the Rhinos, forcing them to flee the village.
Later that spring, the Rough Rhinos attempted to capture the Earth Kingdom's Chin Village in honor of Fire Lord Ozai. During this fight, Sokka reflected the sun in his magnifying glass to distract Vachir. Vachir turned and fired at the source of the light without being able to take aim properly. His arrows missed Sokka; instead they embedded themselves into Yeh-Lu's saddle bag which contained four sticks of dynamite. Yeh-Lu picked up the bag and threw it on the roof of a neighboring house where it exploded, burying Yeh-Lu under debris. While Vachir was still distracted, Katara sneaked up behind him and used her water whip to cut the saddle straps. Vachir fell off and was dragged by his fleeing rhino.
The Rough Rhinos ran into Iroh and Zuko, who had been branded traitors of the Fire Nation, not long after their final encounter with Team Avatar. Vachir shot a lit arrow at Zuko's back, but Zuko sensed the arrow, turned, and broke it apart as it approached him. Zuko then let loose a measured stream of fire which burned a hole in the archer's bow, a hand's width above the archer's hand. The blast passed through the bow and broke the string, leaving Vachir weaponless.
As a Yuyan Archer, Vachir was very confident in his abilities almost to a fault, boasting to the then Prince Ozai that while any of his fellow archers could pin a fly to a tree from a hundred yards away without killing it, he could do the same blindfolded.