Subtitle: Transforming Terrible-Monster (変身超獣 Henshin Chōjū)
Yapool then sent Brocken aboard a space vessel, that was heading home to Earth, hijacking it in the process and possessing one of the crew members, Koyama. While in its host's body Brocken appeared to act normal, but once his host's son found an extra mouth on his hand the guise was revealed. The son informed TAC, who were quick to take action. When Brocken was found out, he fled TAC until he reached one of their HQs, where he took his true monstrous form and attacked the city with his flames. TAC quickly responded with their gunfire and jets, but they were no match for Brocken's strength. During the fray, Hokuto was caught in Brocken's right arm jaws. Minami ejected from her jet and together they transformed into Ultraman Ace, severing Brocken's right arm in the process. At first, Brocken had the upper hand in the battle with its brute strength and laser attack. Then an Ultra Sign was sent by the 4 Ultra Brothers which encouraged Ace, who managed to stand, and destroy the Terrible-Monster with three Ultra Guillotines, severing Brocken's head, arm, and whips, killing the Terrible-Monster. With Brocken dead, his host was soon free of the monster's control.
- Design: Akihiko Iguchi
- Brocken's roars are modified elephant trumpets. They would later be used and modified for the Toho Monster, Titanosaurus.
- There is a brief continuity error during the battle between Ace and Brocken. When using his claw lasers, Brocken has both from his front arms even though one was destroyed when Ace transformed.
- Although not physically seen, Brocken is one of the monsters that makes up Belyudra's Body in Mega Monster Battle: Ultra Galaxy Legends The Movie.
While not appearing physically in the series, a modified variant called Modified Brocken (改造ブロッケン Kaizō Burokken) that appeared under the control of the Guar general Imbiza was talked about in episode 13's voice drama.
- Height: 63 m
- Weight: 46,000 t
- Origin: Yapool's Dimension
- Weakness: The possession victim's hand will have a large eye and a large mouth, because of this the victim must wear gloves to blend in society. Also, the possessed host will not have a shadow.
- Powers and Weapons
- Flames: Brocken can emit twin streams of fire from each of his nostrils.
- Energy Beams: When needed, Brocken can fire missile-strength beams of energy from the beaks on his hands.
- Energy Bolts: Brocken can fire bolts of yellow energy from the tips of the tentacles on his shoulders. Each bolt can either create explosions as large as he or have a shocking effect much like electricity.
- Possession: Brocken can possess a human host. Akira Koyama was one of his possession, he was played by Akiji Kobayashi famous for playing Captain Muramatsu.
- Brocken Hands: When Brocken possess a host, the host's hands sprout an eye and teeth. The hands can also emit a white gas from them.
|Ultraman Ace Kaiju|
|Verokron | Yapool | Chameleking | Vakishim | Garan | Aribunta | Giron Man | Brocken | Alien Metron Jr. | Doragory | Muruchi II | Gammas | Zaigon | Alien Antira | Unitang | Sabotendar | Baraba | Ace Killer | King Crab | Cattle God | Cowra | She-Devil | Hotarunga | Black Pigeon | Android Couple | King Kappa | Zemistlar | Aprasar | Aprasar Fairy | Space Mask | Black Satan | Giant Yapool | Mazaron Man | Yojo | Mazarius | Alien Orion | Sphinx | Alien Hipporit | Lunaticks | Undergroundmon | Gitagitanga | Red Jack | Baktari | Coakes | Bad Baalon | Kaiteigagan | Dreamgillas | Soundgillar | Machless | Snowgiran | Namahage | Alien Fire | Firemons | Alien Steal | Kaimanda | Shishigoran | Iceron | Woo II | Fubugirara | Onidevil | Gasgegon | Daidarahoshi | Hanzagiran | Verokron II | Yapool Woman | Univerlages | Aquarius | Alien Revole | Signalion | Geegon | Alien Simon | Jumbo King|