|Home world:||Planet Coro|
|First appearance:||Ultraman Leo episode 23 "The Mischievous Alien Who Fell Out of Bed"|
|Affiliation:||Alien Coro (Master)|
Subtitle: Rainbow Monster (虹怪獣 Niji Kaijū?)
- Height: 57 m
- Weight: 37,000 t
- Origin: Planet Coro
After being called by his child master, Renbolar flew from their home planet and to Earth to find his master. Renbolar arrived the next day, much to both the children and Alien Coro’s delight, but it also caught the attention of MAC, who tried to evacuate the children. However, Alien Coro proved his control over the seemingly docile monster as he had him doing tricks such as backflips, silly poses, and magic tricks. At MAC's request for the city's safety, Alien Coro had to send Renbolar back home, but suddenly his tail was pulled out by the greedy kids who wanted more. This caused Renbolar to go wild and out-of-control, attacking the city they were in and even MAC as well. Luckily, a storm blew in and the rain frightened Rebolar away.
The next day as Alien Coro was regenerating a new tail, Renbolar returned and devoured a rainbow that appeared in the sky, created by yesterday's storm. Because of this, his strength increased as he resumed his rampage. Gen then transformed into Ultraman Leo and thus the two did battle (comedically) in a boxing-styled battle that went on for well over 7 rounds until Alien Coro literally threw in the towel, hoping to keep his pet monster alive, which Ultraman Leo did by knocking out the monster. The next day, Renbolar awakened but was bounded in chains until Alien Coro’s regeneration was complete. But this didn’t stop the monster as it easily broke throw the chains and resumed his rampage. Gen once again transformed into Ultraman Leo to hold off Renbolar long enough for Alien Coro to finish his regeneration. Finally, the new tail was completed and Alien Coro regained control of his monster. Renbolar apologized to Ultraman Leo, who accepted the apology, as well as the city, and the children. Alien Coro and Rebolar then left Earth peacefully.
- Renbolar's ability to consume rainbows is both contradictory and scientifically impossible. Rainbows are created when the sun's reflection bounces off rain, acting like a prism and creating the colors seen during a rainbow's sighting (usually seen during the aftermath of storms). Renbolar is seen fleeing from a storm as Alien Coro states that he is afraid of water. With this, Renbolar is basically consuming rain. These contradictions are most likely a big scientific inaccuracy.
- Renbolar's roar is a modified Baragon roar.
- Rainbow Consumption: If Renbolar consumes a rainbow, his strength increases 100x his actual strength.
- Flight: Renbolar is capable of anti-gravity flight. Being able to fly through air and space with ease.
- Extraordinary Jumper: Renbolar can do several flips while jumping in mid-air
|Ultraman Leo Kaiju & Seijin|
|Red Giras | Black Giras | Alien Magma | Alien Tsuruk | Kanedoras | Alien Karly | Kendoros | Vekira | Guiro | Ron | Alien Kettle | Bango | Alien Vibe | Antales | Alien Flip | Alien Atler | Alien Wolf | Bat Girl | Batton | Alien Boze | Bock | Dogyuh | Alien Alpha | Northsatan | Garon | Littre | Alien Coro | Renbolar | Carolyn | Alien Sarin Dodole | Gamerot | Alien Clean | Satan Beetle | Pressure | Oni-on | Planet Apple Chicken | Alien Paradai | King Paradai | Uriy | Uringa | Alien Magma II | Rolan | Alien Virmin | White Flower Spirit | Princess Kaguya | Kiraa | Alien Akumania | Ashuran | Sevengar | Taishoh | Alien Atlanta | Alien Mazaras | Specter | Alien Babarue | Black Directive | Silver Bloome | Black Dome | Absorba | Deemos | Black Garon | Blizzard | Mayuko | Hungler | Black Terrina | Satan Mora | Nova | Alien Bunyo | Black End|