From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Hirudegarn (ヒルデガーン, Hirudegān; FUNimation "Hirudegarn") is an enormous phantasm.
Main article: Hirudegarn war
The ancient monster Hirudegarn existed thousands of years prior to the events of the series, on an Earth-like planet in the southern galaxy named Planet Konats. According to the FUNimation dub, Hirudegarn was an ancient, malevolent, wraith-like phantom beast of mist and shadow who "consumed its victims and imprisoned their life-force" (similar to Cell, but on a massive scale). He was apparently turned to stone with the use of an enchanted sword and a pair of enchanted ocarinas and then sealed away in a temple by the ancestors of Tapion and Minotia until a sect of warlocks (known as the Kashvar) arrived on Planet Konats and used their dark magic to bring the monster back to life with the intent of destroying the Conutsians and all life in the universe different from themselves. The monster immediately went on a rampage, killing everyone who tried to get in his way, and devastating the planet. Tapion and his brother Minotia managed to freeze the monster in his tracks by each playing a pair of enchanted Flutes found at the temple, giving a priest the opportunity to cut the monster in half with an enchanted sword. Since Hirudegarn could not be killed at the time, his upper half was sealed within Tapion and the other half within Minotia, and in this way the brothers became legends. Fearing that the Kashvar would try to revive the monster again someday, the brothers were separated and each was sealed inside a Music Box by the Kami of Planet Conuts and shot into different galaxies. The Music Box that held Tapion eventually landed on Planet Earth. The priest vowed to release the brothers once the Kashvar were brought to justice, and it is assumed that the Kashvar were hunted down over time.
Dragon Ball Z: Wrath of the Dragon
A thousand years later, in the present, the last of the Kashvar, Hoi, had vowed to resurrect the monster to rule the universe. He released Hirudegarn's lower half on a distant planet and easily disposed of Minotia, who got crushed under the feet of the monster, and sealed the lower half inside of himself to summon at his leisure. On Planet Earth however, Hoi switched to a more tactical plan and spied on Son Gohan and Son Videl (as the Great Saiyamen) as they fought crime. Both were summoned from their school again to rescue Hoi, who was pretending to be suicidal to gain their trust and sympathy. Hoi then told the two about the legendary hero, Tapion.
Both were anxious to see who this Tapion was, however, neither they nor Son Goten, Trunks Brief, or Son Goku were able to open the seal. Seeing no other alternative, the fighters of Earth collected the Dragon Balls so they could summon Shen Long and wish for the seal to be broken. Shen Long succeeded, and Gohan, Videl, Goten, Trunks, Goku and Bulma, along with Hoi, met Tapion for the first time. Tapion was very angry at them all, however, because it had been a bad idea to release him. He demanded that he be sealed back again, but by his release the Music Box had shattered, so that proved impossible. Trunks, however, was determined to bring him food and drink as he saw Tapion as an older brother.
Shortly after Tapion's release, Hirudegarn's lower half (summoned by Hoi) was busy wrecking a city. Gohan and Videl arrived at the scene to investigate, but shortly after they arrived they were almost swept away by the monster's tail. They executed their Great Saiyaman poses, however, Hirudegarn's legs were not impressed. He threw the two each to a side of the street and Videl lost her helmet and Gohan lost his turban and sunglasses. Gohan immediately set up a counter-attack, with Videl supporting him. After the short battle Videl thought Gohan had won, however Gohan said it wasn't over yet. Then both heard the same Flute melody that they heard when Tapion was released and they noticed the monster was gone.
Later, Tapion explained everything to Bulma, and revealed that Hoi had deceived them all. Bulma was angered at hearing it, and she decided to create another oracle. At the same time Hirudegarn's lower half was summoned by Hoi once again wrecking havoc, as he drew four men and a woman into his tail to devour their life energy. Hoi directed his power to release the upper half of Hirudegarn. He finally succeeded in this, and with the monster back together nothing could stop him. However, the Z Fighters resisted magnificently. Goku, Gohan and Goten were the first ones to launch a counterattack, but just as Gohan was crushed by the tail, Vegeta threw himself into the line of battle after saving Gohan. Goten and Trunks decided to use the Fusion Dance to become Gotenks as a Super Saiyan 3, however this resulted in Hirudegarn evolving. In his new form Hirudegarn mowed Gotenks down to the ground, smashed Gohan and Videl into a building and Goku was thrown into some rubble. Tapion played the ocarina again and managed to seal Hirudegarn inside himself. He then ordered Trunks to kill him with his sword, which would destroy the trapped monster. Trunks hesitated but was about to do it when Hirudegarn broke free as Tapion couldn't contain the whole monster by himself. His ocarina is destroyed in the process. Hoi (who had been watching the whole fight) mocked Tapion for being so foolish, but was killed when Hirudegarn crushed him underfoot. Nevertheless, Trunks tried to fight Hirudegarn with Tapion's sword and managed to cut off the monster's tail, but then Goku arose as a Super Saiyan 3, taunted the monster to anger it (as that was its weakness), and used his Dragon Fist to pierce through Hirudegarn, obliterating the monster.
- Chou Makousen – Lets out a massive energy beam from the mouth.
- Dark Eyes – A Blast 1 attack that allows Hirudegarn to avoid a single attack. Used to represent his mist ability in the Budokai Tenkaichi series.
- Drain Life – Hirudegarn can absorb people's energy with his tail much like Cell.
- Explosive Wave – Creates a weak explosion for protection with Hirudegarn himself serving as the nexus.
- Genma Kaenhō – Genma Kaenhō (幻魔 火炎砲, Genma Kaenhō; Literally meaning "Phantom Demon Blaze Cannon")
- Gigantic Flame – Spits out bolts of powerful, blazing fireballs.
- Ki Blast
- Mist – Hirudegarn can turn into a mist to prevent damage and reappear in front of the enemy for a surprise attack. This move seems to be reflex, making Hirudegarn invincible due to his intangibility. This technique can only be bypassed when Hirudegan is physically attacking, which makes him briefly tangible as he needs to be tangible to hit something.
- Super Explosive Wave – Creates a giant explosion with Hirudegarn himself serving as the nexus.
Hirudegarn's name comes from the Co-Producer, Seiichi Hiruta, who did not like the original design of Hirudegarn, demanding that they redesign the character. When he saw the new design, his jaw dropped. The sound effect for jaw dropping in Japan is gān (ガーン, gān), so they named the character Hirudegān.
- Hirudegarn is the biggest non-transformed movie villain, with the exception of the Big Gete Star.
- Hirudegarn eating people is similar to Cell absorbing people. His second form also looks like Cell's first form.
- Hirudegarn's existence bears some similarities to that of Majin Buu. Both were created to be instruments of destruction, were sealed away for thousands of years, and later revived by their creator or their creator's descendant. Like Buu, Hirudegarn ends up killing the one who revived him, though in Hirudegarn's case, it seemed to be accidental.
- Hirudegarn also shares similarities with King Piccolo, as both were legendary creatures that rampaged on a planet centuries before the events of the series, both were sealed away for decades, only to be released and begin their reign of terror anew, and both were eventually killed from Goku punching though their midsection.
- Hirudegarn is possibly one of the strongest villains in Dragon Ball Z as he easily defeated Super Saiyan 3 Gotenks with one hit, and even defeated Gohan. However, Super Saiyan 3 Goku managed to defeat Hirudegarn by discovering his weakness and using his Dragon Fist technique.
- In the instruction booklet of Dragon Ball Z: Budokai Tenkaichi 3, where they name all the characters voiced in the game, Hirudegarn is mistakenly spelled Hildegarn. In the Japanese version of the show, he is named Hildegarn.
- Hirudegarn is the only main film villain to be defeated by a Super Saiyan 3.