|"Whatever it is, it's bad! Bad! The city's probably doomed! We're probably doomed!"|
|— Ho Tun's typical panicking.|
Ho Tun was a student at the Beifong Metalbending Academy. One of Toph's first three students, he was a nervous teenager who was constantly worrying about doom, as well as his parents, who lived in Yu Dao.
One year after the conclusion of the Hundred Year War, Toph found Ho Tun in a ramen house raving over having swallowed half of a spider wasp in his soup; his over-emotional state inadvertently caused Toph's bracelet to vibrate slightly. Ho Tun later enrolled into the Beifong Metalbending Academy near Yu Dao, along with two other earthbenders who had similarly affected the bracelet, in order to begin learning metalbending. However, Ho Tun's improvement was slow, and he had yet to move a single coin when Sokka visited the academy.
When a rival firebending school under the leadership of Master Kunyo forced them out of the school, Sokka bought him and the other students three days during which they could prepare for a "match to the sit", a battle in which the first team to force someone on the opposite team to sit down would win the rights to use the building. When Sokka devised a plan to get the students to metalbend by creating a fake winged boar spirit out of metal, Ho Tun panicked, and the plan failed. After several unsuccessful attempts to metalbend, Ho Tun and the rest of his classmates decided to leave in order to avoid "doom". However, as they were heading out, they overheard Toph saying to Sokka that she had expected them to become metalbenders, but that it was unjust of her to force them to become something that they were clearly not. Moved by her statement that she "expected them to be something", Ho Tun and his friends discovered the secret of metalbending.
The next day, when Toph was about to sit down in defeat before Master Kunyo and his firebending students, Ho Tun halted her by metalbending a coin at her behind. He, The Dark One, and Penga proceeded to defeat the firebending students and their master by metalbending several coins at them. Ho Tun thanked Toph for believing in him, as, although she never said a kind word about him, he admitted that she was the first one who expected him to be something more than a "wimp". In the fight for the Harmony Restoration Movement, the metalbending students helped Toph when she was in trouble by metalbending the Fire Nation soldiers' helmets.
Saving Sifu Toph
After Toph departed from the academy to see her friends, Ho Tun, The Dark One, and Penga became its temporary instructors. He elaborated on The Dark One's poetic instructions regarding chi by saying that they should concentrate and gather the chi deep in their bodies and use it to feel the metal around them. At that moment, Sokka arrived, telling the three that they needed to come with him. Seeing Penga try to flirt with Sokka, Ho Tun warned her that the situation looked serious. He let out a gasp when the warrior added that it was Toph who needed their help.
The students arrived to the town where the Earthen Fire Refinery was located, where they met up with Aang, who explained the situation to them: Toph and several others were trapped underground and he could not dig them out due to the iron ore deposits in the ground. Ho Tun asked if that meant he needed their metalbending, which Aang confirmed. Katara added that Toph stated it to be like spider ants stomping beneath their feet, much to Ho Tun's dismay, because it was an exercise in which they were blindfolded and had to stand in a sand pit while throwing giant metal plates back and forth over their heads, an exercise which if they failed to complete, they would be stomped by the plates. Ho Tun did take offense when Penga said the plates were bigger than him. The metalbender was unsure if he could do it, but Aang motivated him by saying it was what they trained for. He promptly asked if their "gut furnaces were ready"; once they were set, he called on them to metalbend. Ho Tun screamed upon revealing a giant iron mask and soon doubted their abilities again, but was once more motivated by the Avatar, who told them they were the three best metalbenders in the world outside of Toph and the only ones who could complete the task. Continuing, he told Aang that they needed him to ensure that the dirt did not collapse back into the mine before telling everyone to give one last heave. With that move, they freed the caved-in group. Toph complemented them on their job before, much to Ho Tun's worry, she collapsed into her father's arms. Lao assured them that she was just exhausted and would be fine. The student noted that Toph looked small and almost fragile, to which Penga warned him that Toph would pummel him if she heard such words. Upon learning that Lao was Toph's father much to Penga's shock, Ho Tun asked if she thought their sifu just popped out of a rock.
Defending the Earthen Fire Refinery
The students continued to stand near their instructor as she rested. However, when they learned that Aang was about to destroy the Earthen Fire Refinery and Toph awoke, she called on them to help her stop him. They raised an earthen wall to stop his attacks. They were blown off the wall by Aang's air rings but landed softly on their feet before returning to the battle. Toph called on them to metalbend, but their attacks were dodged. Ho Tun soon grew scared, however, upon noticing that the spirit, General Old Iron, was approaching them. With an intense battle between the spirit and Avatar, Toph again called on the three, but this time to help Aang by peeling off Old Iron's armor with their bending, just like the forest bowing to the east wind exercise. They were able to do so and thus give Aang an open shot to the spirit's chest, but Old Iron soon noticed that the four metalbenders were destroying his armor, thereby causing Old Iron to turn his attention toward them. Toph told them to run while she held him off, though Ho Tun and his students did not do so. They soon watched as Aang delivered a severe blow to Old Iron and the vanquished spirit gave a speech about how humans were more powerful than him before walking away.
Three months after the event, Ho Tun participated in the parade for the new Spirits' Friendship Festival, tapping a small drum as the procession made its way down the town's main street.
- Ho Tun represents the vice of fear, which the Beifong Metalbending Academy helps him surmount.
- Gene Luen Yang was originally going to have Ho Tun constantly obsessing over death, but the idea was deemed inappropriate by Nickelodeon for the target age group. Therefore, Gene replaced it with an obsession with "doom", leading to what he feels to be a more comic effect.
- Ho Tun was the first student to learn metalbending, and thus became the second person, in addition to being the first male, to ever bend metal.
- Upon figuring out how to metalbend, Ho Tun became Penga's new crush, much to his surprise.