|Home world:||Planet Antira|
|First appearance:||Ultraman Ace episode 10: "Decisive Battle! Ace vs. Goh Hideki"|
|Affiliation:||Zaigon & Beryudora (Back)|
Subtitle: Transformation Phantom (変身怪人 Henshin Kaijin?)
- Height: 2 m
- Weight: 150 kg
- Origin: Planet Antira
When the monster Zaigon appeared to devastate the city, Hideki Go suddenly appeared in front of Seiji Hokuto, ignoring Seiji's calls to move out of the way, and fired his weapon at Zaigon, causing it to disappear. As TAC congratulated Go on his efforts, he told them his weapon was called the Ultra Laser. Jiro Sakata was ecastic at seeing his brother figure return, before being gently pulled away as Goh was injured during the attack and sent to TAC hospital for recovery.
TAC would then settle into an intense debate of whether to accept Go as a new member, and Seiji is scolded for arguing about how Go's actions prevented him from firing at Zaigon. Afterwards, when Seiji and Yuko visited Go in his room with Jiro and his female companion, Seiji begin to suspect Goh when Jiro saw Goh handle the chopsticks he had been given to eat the food Jiro gave him in his left hand, when Go is supposed to be right handed.
Just then Zaigon reappeared and Go leapt out of his bed, locking the door and trapping Jiro inside. Hokuto tried to open the door, but Go shot at him, and that was when he revealed his true identiy as Alien Antira. Hokuto quickly freed Jiro, who went after the alien, angry that it had disguised itself as his idol, but was taken hostage. Hokuto freed Jiro, and Antira was finally killed by a shoot from Hokuto.
- Alien Antira is left handed, which mirroring the old superstition that left-handed people were evil and him being one of Yapool's agents
- Alien Antira's suit would be modified to Alien Simon suit.
- Although not physically seen, Alien Achira is one of the monsters to make up Beryudora's back in Mega Monster Battle: Ultra Galaxy Legends The Movie.
Powers and Weapons
- Disguise: Alien Achira can disguise himself as a human, specifically Hideki Go. However, the human form is more evil-looking than normal.
- Laser Cannon: Alien Achira is equipped with a powerful laser cannon. He tricks TAC by calling it the "Ultra Laser".
- Extraordinary Jumping: Alien Achira can jump very high into the air.
|Ultraman Ace Kaiju & Seijin|
|Verokron | Yapool | Chameleking | Vakishim | Garan | Aribunta | Giron Man | Brocken | Alien Metron.Jr | Doragory | Muruchi II | Gammas | Zaigon | Alien Antira | Unitang | Sabotendar | Barabas | 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 Hipporito | 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 | Fubigirara | Onidevil | Gasegon | Daidarahoshi | Hanzagiran | Verokron II | Yapool Woman | Univerlages | Aquarius | Alien Revole | Signalion | Geegon | Alien Simon | Jumbo King|