Astromons is constantly hungry and is very, very violent in battle, going as so far as willing to eat his opponents. Brutal and unpredictable, there's no telling what Astromons can do in combat.
Debut: Ultra Kaiju Battle Royale
Astromons along with Snowgon and Femigon were led into battle with Dorobon to fight against the other four Ultra monsters Gomora, Red King, Eleking and Antlar at Hokkaido. Astromons was the second monster to appear there, disguised as the Tigris Flower before then spraying knock out gas and then rising up, revealing his true monster form.
Astromons began his attack by attacking Eleking, wielding up his hook hand and then slashing it against Eleking. Eleking then moved to his side and then wrapped his tail around Astromons, sending volts of electricity against Astromons, shocking him. Astromons then sprayed his acidic mist at Eleking's area, causing Eleking to stagger away from him. Astromons then swung his hook arm against Eleking then staggered back in case.
Eleking retaliated by firing light blades at Astromons, causing Astromons to flail around. Astromons and Femigon then regrouped with each other to better combat against both Antlar and Eleking. Astromons and Femigon then fired both of their fireballs and acidic mist towards Antlar and Eleking, only for Antlar to retaliate by firing a big energy blast against the two, causing a big explosion to occur in front of Astromons and Femigon.
Astromons then got back up and then ran towards Gomora and Antlar, swinging his hook arm around like a madman. Antlar then bit on Astromons's hook arm, causing Astromons pain. Astromons then lashed out his whip arm against Gomora's face. Gomora was hit, but reacted by lashing out his own tail against Astromons. Then from out of the blue; then came Ultraman Joneus appeared to deal with the Ultra monster situation. Ultraman Joneus took quick notice of Astromons and then blasted his Planium Beam against him, causing Astromons to stagger back.
Astromons then activated his flower gorge and then ran up to both Gomora and Ultraman Joneus. Ultraman Joneus dived at Astromons, punching at him hard; sending Astromons flying back. As Femigon, Dorobon and Snowgon then all left retreating, Astromons was the last member of his team still standing; Astromons then got up and went ballistic and attacking EX Red King, who he was not scared of. However, Astromons was no match for EX Red King who in bit down on Astromons's shoulder and tore it off.
Astromons slashed his hook hand down across EX Red King's chest, causing EX Red King great pain. EX Red King then punched against Astromons's chest, creating a big impact and sending Astromons flying against Ultraman Joneus. Ultraman Jonues then grabbed Astromons and then used his Boomerang Guillotine against him; causing Astromons to stagger back. Finally, Ultraman Joneus used his Planium Beam against Astromons, creating a big explosion. Astromons then got up and flew away, retreating.
Nemesis vs. Gokidon's Army
Astromons later reappeared as one of Gokidon's many monsters that he used to attack a Canadian city and then to target Nemesis and Baron Bloodsport. Astromons was the last monster Gokidon summoned to battle; Gokidon then fired out another round and summoned another monster; which it was Astromons. Gokidon and Astromons then both appeared to combat Nemesis and Baron Bloodsport, with Astromons fighting off Baron Bloodsport and Gokidon fighting off Nemesis. Nemesis then let out a loud roar that shook the ground; Astromons and Gokidon then stagger around, doing their best not to sink into the ground. Baron Bloodsport fired his Black Beam at Astromons, to which Astromons staggered back from. Astromons then fired a stream of flames from his mouth at both Nemesis and Baron Bloodsport. Nemesis then blocked the flames and bazooka rounds.
Astromons whipped his whip arm and reeled Baron Bloodsport in, then hitting against Bloodsport's head with his hook arm. Baron Bloodsport felt the hook arm hit his head. He then uses both of his arms to grab hold of both of Astromons arms and pulled hard. Astromons struggled and then lifted and threw Baron Bloodsport at Nemesis, smacking Nemesis backwards. Astromons then flew up and then sprayed acidic mist from his mouth down at Baron Bloodsport and Nemesis's area. Nemesis then grabbed Astromons and used him as a meat-shield, having his acidic mist hit Gokidon instead. Astromons then whipped his whip arm around Nemesis and then breathed a stream of flames at Nemesis's and Baron Bloodsport's area, only for Nemesis to then grab onto and lift Astromons, throwing him at Gokidon, toppling Gokidon and pinning him down to the ground, defeating him.
As Gokidon then admitted defeat, the ground then shook and opened up a giant crevice; Gokidon and his monsters then fell down below and then the crevices closed, Astromons included. What became of him exactly after that is unknown, but he most likely survived still.
- Acidic Mist: Astromons can emit an acidic mist from the flower on his stomach that can dissolve entire buildings in just a few seconds.
- Right Whip Arm: Astromons has a whip for a right arm, which he can use to batter and strike at enemies.
- Left Hook Arm: Astromons has a hook for a left arm, which he can use to batter and strike at enemies.
- Flower Gorge: Astromons' stomach flower has its own mouth, which is capable of eating anything in just a few minutes if it gets stuck inside it.
- Flight: Astromons can fly through the air at high speeds by simply flapping his arms. Astromons can fly at Mach 3.
- Flames: Astromons can spit a flame of 10,000 degrees from its mouth.
- Astromons was originally supposed to first appear in a RP along with Sadola and Gabora, in where he would have fought against FlamingoMask, Kamen Rider Kiva and Kamen Rider 1 and would have acted as the main antagonist in the RP, but this was dropped. His second attempt for his debut also had him originally going up against Inspector Cypher, but this too was also dropped. His third and finally successful attempt for is debut was Ultra Kaiju Battle Royale.
- He is one of Gallibon the Destroyer's favorite Ultra kaiju.
- Astromons's name comes from the English term "Cosmic Monster," when translated into Japanese is "Astro Monster".
- Astromons was initially named "Flower King", in the screenplay he was labeled as "Astro King".
- Astromons' roar is a re-used Goliath roar.
- Astromons was created from a modified Bemstar suit. Furthermore, Astromons pays tribute to Bemstar, since both shared a common subtitle and functions (Bemstar has a mouth on his stomach, like Astromons).
- Also, fittingly enough, the Astromons suit would be "unmodified" for Bemstar's reappearance in Ultraman Taro as Reconstructed Bemstar.
- Astromons is said to be a "Super Choju," however there is no direct reference between him and Yapool or any proof that this fact is accurate.
- However, this title might be due to the ease with which he defeated Oil Drinker, who was the last of the Choju.