|First Appearance:||Ultraman R/B Episode 1: Beginning of Ultraman|
|Latest Appearance:||Ultraman R/B Episode 24|
|Affiliation:||Makoto Aizen (Summoner)|
- Bone: Flame Bone Beast (火炎骨獣 Kaen Kotsu-jū)
- King: TBA
- Regina: TBA
Grigio Bone was a mythical monster featured in legends of Ayaka City, crashing to the Earth in a meteorite known as the Ayaka Star, along with Ultraman Rosso and Ultraman Blu 1300 years ago. People attacked him, but Grigio Bone swallowed them whole. He was given the name Grigio-sama by the locals, and Ayaka City was named after the incident.
In the present, Grigio Bone was summoned by the power of a Kaiju Crystal by Makoto Aizen. First spotted by a couple taking photos, the footage of him was dismissed by Katsumi as CGI until Isami revealed his device had detected the monster's activity as well.
Grigio Bone then reappeared the next day when he emerged from a building and decided to go on a rampage after spotting Katsumi Minato and Isami Minato looking at him. The two brothers then went into a park where they decided to distract the kaiju to save a young boy named Kiwamu and just as they were about to be burned to death, the two brothers were given the R/B Gyro and Crystals. Katsumi and Isami then transformed into Ultraman Rosso and Blu respectively, fighting for the first time as an Ultra.
A fierce battle began in Ayaka City, with Grigio Bone fighting against Rosso and Blu who were seemingly inexperienced in battle. Blu made the first move, but Grigio Bone dodged his Jumping Kick easily and threw him back at Rosso. The kaiju then accelerated at the duo, but Rosso stopped him with his Flame Bullet and Blu used his Water Jet for the first time as well. As the two Ultramen and kaiju fought on, Rosso pulled up a tree from the ground and used it against the kaiju but the kaiju then caught it in his mouth and used Rosso as a shield against Blu's kick. Grigio Bone then unleashed his Bone Breather on the brothers.
After a discussion, Rosso and Blu decided to switch R/B Crystals and for the first time, switched forms as well. Rosso used his Barrier to block Grigio Bone's Bone Barrier and while they were fighting, Blu launched his Fire Bullets at the kaiju and, inadvertently, his own brother, causing the two of them to argue leading to an awkward moment with Grigio Bone which lasted until the kaiju scared them with his roar.
Afterwards, the two brothers worked together in combat, and even with their Color Timers flashing after attacking the kaiju with their W (Double) Kick, they didn't let up as they grabbed Grigio Bone, knocked him down, then swung him around with their Ultra Swing. The two Ultramen then encased Grigio Bone in a Splash Bomb and sent him flying with the Flame Equilix. In the end, Rosso and Blu switched back to their original forms and struck down Grigio Bone with the brothers' Flame Sphere Shoot and Aqua Stream and the kaiju exploded in the process and Makoto reclaimed the kaiju's Kaiju Crystal in the aftermath.
- Suit Actor: Hiroyuki Arai.
Grigio Bone (グルジオボーン Gurujio Bōn) is the monster that came to Earth in the Ayaka Comet 1300 years before the start of Ultraman R/B. He was regarded as a legend within the city of Ayaka, until his reawakening in modern times. He is said to be a ferocious monster with unlimited strength.
- Height: 60 m
- Weight: 62,000 t
- Origin: Mt. Ayaka
- Powers and Weapons
- Meteor Travel: Grigio Bone is able to travel through space as a fire sphere.
- Bone Breather (ボーンブレスター Bōn Buresutā): Grigio Bone's primary attack where he spits flames of up to a million degrees out of his mouth.
- Acceleration: Grigio Bone has the ability to run at fast speeds.
- Tail Whip: Grigio Bone's tail is strong enough to knock down two Ultras at once.
Grigio King (グルジオキング Gurujio Kingu) is a subspecies of Grigio presumably more powerful than Grigio Bone. This king-type species will make its appearance in episode 14.
- Powers and Weapons
- Back Cannon: Grigio King has a large cannon mounted to his back.
- Body Spikes: Grigio King has several spines and blades across his body, which he can presumably use in melee combat.
Grigio Regina (グルジオレジーナ Gurujio Rejīna) is the queen type, and presumably most powerful species of Grigio, that will make its appearance in episode 23.
- Powers and Weapons
- Body Cannons: Grigio Regina has at least three cannons mounted on her shoulders and chest.
- Body Spikes: Grigio Regina has a variety of spines and blades across her body, which she can presumably use in melee combat.
- Spiked Tail: Grigio Regina's tail is split in two, and both points are covered in sharp spines. Considering Grigio Bone's earlier use of his tail as a weapon, Regina's is likely even more effective.
- Grigio means "Gray" in Italian.
- In Grigio Regina case, Regina is also Italian/Latin for "Queen".
|Ultraman R/B Kaiju & Seijin|
|Grigio Bone | Black King | Gargorgon | Red King | Gue-Basser | Mecha Gomora | Aribunta | Horoborus | Grigio King | Grand King Megalos | Kamisori Demaaga | Grigio Regina | Reugosite|