Star Bem Gyeron (ギエロン星獣 Gieron Seijū) (also known as Star Beast Gyeron, Gyeron Starbem, or just Gyeron) is a birdlike alien Kaiju that first appeared in the series, Ultraseven. He appeared in episode 26.
Subtitle: Regeneration Monster (再生怪獣 Saisei Kaijū)
Star Bem Gyeron was an alien who lived alone on a planet which shared his name. The beast became a victim of the Ultra Garrison's experimentation on a new rocket that destroyed his homeworld. The Gyeron monster pursued the rocket's origin and left for Earth to destroy it out of vengeance for the destruction of his homeworld. The Ultra Garrison quickly picked up on the monster's presence and tried to stop the monster while battling it in space, but the beast's reflective body parts allowed him to resist their efforts. Shortly after landing on Earth however, the Ultra Garrison was able to corner the monster and using a series of bombs, the monster from Gyeron was blown to pieces by their bombs. Later that night however, the chunks that made up the monster's body reformed back together and it was revived, to which he flew off into the night.
The next day, the monster was found in an open field by the Ultra Garrison. This time however the monster resisted their weapons and downed their jets with a combination of his radioactive mist and his energy rings. Once the Ultra Garrison was taken down, Dan transformed into Ultraseven to battle the alien monster. Star Bem Gyeron proved to be a challenge for the Ultra by using his arms to reflect Ultraseven's Eye Slugger multiple times, and using his energy rings to damage his right arm. Ultraseven continued to fight back and by absorbing enough sunlight, Ultraseven tore off the monster's right arm and slit the monster's throat with the Eye Slugger, agonizingly killing the creature from the dead planet Gyeron.
- Suit actor: Kunio Suzuki
- Star Bem Gyeron has one of the largest amounts of alternate names in the Ultraman Series, mostly because of the fact that no one English dub or subtitles for the episode can decide on his name.
- Gyeron's episode was made as a satire against nuclear deterrents and was made as a reflection of the Cold War.
- Ironically after March 2011, the Gyeron monster's episode was temporarily removed from rotation in Japan due to the Fukushima Daiichi nuclear disaster. This is due to a scene where Gyeron wipes out a Power plant with a giant wave after he lands in the sea. This makes Gyeron the second of two characters from Ultraseven to have their episodes removed from rotation, with the other one being Alien Spell. However, Gyeron's appearance in Ultraman Geed shows that unlike Spell, Gyeron has not been banned from reappearing, and he also appears relatively often in stage shows.
- Although not physically seen, Gyeron is one of the monsters that makes up Beryudora's right arm in Mega Monster Battle: Ultra Galaxy Legends The Movie.
- In the middle-to-late 1990s, footage of Star Bem Gyeron was used for the TNT, TBS, and Cartoon Network show Cartoon Planet. Star Bem Gyeron footage was used to depict an alien in the recurring sketch entitled 'Messages from Outer Space' that would feature other Ultraseven Kaiju broadcasting to Space Ghost, Zorak, and Brak on Cartoon Planet. In his featured message, he was called Krell from the Gyron Galaxy.
- Gyeron makes a surprise appearance in the Comedy Central era of Mystery Science Theater Hour spinoff of Mystery Science Theater 3000, hosted by Jack Perkins, played by head writer Michael J. Nelson. He used a prop of Guiron of the Gamera series and a small Gyeron figurine.
- Gyeron was meant to be colored reddish-maroon, but was changed later.
Star Bem Gyeron reappeared in this series, making its first reappearance after 49 years. It first appeared in Hoshiyama at exactly 10:00 AM and immediately found himself fighting against Ultraman Geed in his Primitive form. During their fight, even though Geed showed signs of being tired, he managed to hold even ground against the kaiju. After Gyeron exhaled radioactive gas on Geed, the latter transformed into his Royal Mega-Master form and quickly destroyed him with his Swing Sparkle. However, this was only the fifth time in a row that Star Bem Gyeron was destroyed.
During the first time the Kaiju did appear in the city, Geed was introduced the Kaiju and during their first fight, Geed exclaimed in pain from trying to chop off Gyeron's armored wings but managed to hold his own against the kaiju. He then transformed into his Acro Smasher form, calmed him down with his Smash Moon Healing, and let him fly away. The second time he appeared, Gyeron went up against Geed in his Solid Burning form after the latter prevented the former from attacking with his Beam Coil and after hitting him a few times on his wings, Geed tossed Gyeron and destroyed him with his Strike Boost. On Gyeron's third attempt, he went up against Geed in his Royal-Mega Master form in a short, losing battle and was destroyed again, this time by his Vulcan Sparkle. On the fourth time, Ultraman Zero took the role of the hero and took on Gyeron in his Beyond form. He tossed Gyeron into the sky, only for Gyeron to use his wings to fly and attack Zero aerially. Zero used his Quattro Sluggers on the kaiju, but they reflected back to him, and so Zero ended up destroying Gyeron with his Bulky Chorus.
Afterwards, Riku Asakura, Laiha Toba, and Moa Aizaki discovered that every day, Gyeron somehow regenerated from being blown to bits every time he was seemingly destroyed. They tried to collect the kaiju's remains so they can get rid of them, but right before 10:00 AM again, the pieces evaporated and reformed into Gyeron once again. That round up to the fight that resulted in Geed using his Swing Sparkle on the kaiju. Thanks to Mayu, however, Moa figured out why Gyeron kept regenerating: the Kaiju had a relatively high amount of body fluid resulting from its planet's extremely high surface temperature and when it got frozen, it's biological activity shut down, and when it does, it can't turn into vapor and reform.
The sixth day then came and Gyeron reappeared once again and Riku once again transformed into Geed to fight him once again. Due to his experience fighting the same kaiju, Geed held the upper hand over Gyeron, but the Kaiju turned the tide in his favor later on, but Geed once again transformed into his Royal-Mega Master mode and quickly regained the upper hand, with Zero Beyond shortly appearing afterwards as he set up a barrier dome in a 1 km area where the two were fighting. Geed then used the Ultraseven Ultra Capsule in conjugation with his King Sword to fire the Slugger Shot at Star Bem Gyeron, which destroyed him again, and this time, to make sure he doesn't regenerate again, Riku, Laiha, Moa, and Leito Igaguri made sure to collect up the kaiju's frozen remains with help from the citizens of Hoshiyama. Afterwards, the AIB transported them all throughout the universe and kept permanently frozen, finally ending Star Bem Gyeron's reign of terror on Earth. Surprisingly, Kei Fukuide was seen with the kaiju's Kaiju Capsule as it was hinted that he used Gyeron to test Geed's capabilities.
- Suit actor: Kazunori Yokoo
- Since Geed does not focus on the World of the Land of Light's continuity, Gyeron was portrayed differently from its predecessor. Its appearance in the series was due to the wish of writer Uiko Miura, who was reported to have submitted a proposal on said monster multiple times in the past.
- The original Gyeron in Ultraseven exploded into green slimy flesh before they reform, but this changed in Geed as blue crystals due to the necessity to avoid clashing with the chroma key green background. Gyeron's flesh's vulnerability to low temperature was due to Planet Gyeron being an extremely hot planet.
- Japanese fans reacted to Gyeron's reappearance in Geed with much backlash, not pleased by the monster's usage in the episode. Its reappearance does not do the original's tragic nature justice, and is merely a minion of Kei Fukuide. Many fans have said they would've just preferred the reuse of Saramandora for its episode. However, there are also viewers who believed that adapting the original monster's tragic backstory would be too unbearable for current audiences.
- Height: 50 m
- Weight: 35,000 t
- Origin: Planet Gyeron (the 7th Planet of Char Constellation)
- Powers and Weapons
- Armored Wings and Head: Gyeron's arms and head possess mirror-like attachments, they can reflect objects and light with great intensity.
- Beam Coil (ビームコイル Bīmu Koiru): Gyeron can generate and fire small energy rings from his hands. This can also be used in close combat to shock enemies.
- Radioactive Gas (放射能ガス Hōshanō Gasu)/Gyero Ash (ギエロアッシュ Giero Asshu): The Gyeron monster can exhale radioactive gas from his beak.
- Reformation: Should the Gyeron's body be blown or cut apart, the pieces can join back together in a few hours. In Ultraman Geed, it takes about 20 hours to get reformed.
- Flight: Thanks to his wings, the Gyeron is capable of flying on both atmosphere and outer space environments.
- Gyero Spark (ギエロスパーク Giero Supāku Unused)