Subtitle: Underground Monster (地底怪獣 Chitei Kaijū)
- Height: 30 m
- Weight: 18,000 t, 20,000 t (Taiga)
- Origin: Underground Ibaraki Prefecture
Pagos was an ancient monster who had ravaged Beijing in search of uranium to feed upon. Once his consumption of uranium was full from Beijing, Pagos turned his attention to Japan to feed on Nuclear Energy from a newly created industrial plant.
Pagos later surfaced in the middle of a field where it attacked a small girl and boy who had found a capsule full of uranium, disguised to look like an egg. After the capsule was lost in the scuffle between the monster and the kids, Pagos resumed its trek to attack the industrial plant. After the monster destroyed the plant, a few missiles were launched that doused Pagos with chemicals that solidified the kaiju into stone. Pagos then fell apart into stone fragments.
- Pagos was the first of many monsters who originated from a modified Baragon suit, followed by Neronga, Magular, and Gabora. Much like the rest of these monsters, except Gabora, Pagos also possesses the same roar.
- Originally Gomess was planned to appear in the episode in the monster's place instead, however due to Tsuburaya being forced to return the Godzilla suit back to Toho Co. LTD, Pagos was created in its place thanks to the suit being loaned by Toho.
- During Ultra Q's planning phase, an episode where a second Pagos would appear and battle against Peter was in the works, as well as one where he would fight Garamon and Kemur Man was also planned, but the episodes were never made.
- Originally Pagos was going to appear in episode 9 of Ultraman, but Tsuburaya decided to create a different monster instead; Gabora.
- Pagos was meant to appear in episode 32 of Ultraseven as the controller of Rigger's planet, but was replaced by said monster.
- Episode 29 of the series Ultraman Max is supposedly a tribute to Ultra Q, with Pagos planning to return but due to the death of its corresponding writer from said monster's debut episode, Pagos was replaced with Geronga, a new monster that resembles the Baragon archetypes from Ultraman, particularly Neronga and Pagos.
- Although not physically seen, Pagos is one of the monsters that makes up Beryudora's body in Mega Monster Battle: Ultra Galaxy Legends The Movie.
- Old promotional photos from Ultra Q showed Pagos fighting Peguila; as well as the two of them fighting Kanegon.
- Pagos has an eyelid mechanisim only used for one scene. He also has an inner light in his iris that glows when he detects uranium.
After over 50 years of absence from a mainstream series or movie since debuting, Pagos returns.
Pagos was accidentally summoned by Alien Zelan Oshoro via an alien device, who wanted to summon Gymaira instead. It was frightened and pushed out of its natural habitat by Gymaira, who was draining the Earth's energy. Pagos emerged from the underground and started rampaging through the city, prompting Hiroyuki Kudo to act and transform into Ultraman Taiga. Taiga's attacks, including the Hell Slash, were ineffective against Pagos' tough hide, so he switched to Ultraman Titas, who was briefly able to beat Pagos with sheer might. However, the tables turned when Pagos used its energy drill attack, forcing Titas into a corner. He then tagged out with Ultraman Fuma, who ended Pagos by slicing its underbelly with an energy blade. As Pagos died, it shed a single tear and turned to stone. EGIS and Maria inspect Pagos' corpse after Taiga was defeated by Gymaira, but when Gymaira returns, the tremors caused by him caused some pieces of Pagos to fall off. The rest of Pagos' corpse is slowly dismantled and taken away by dump trucks after Gymaira is defeated.
- This marks the first time Pagos fights an Ultra Warrior.
- In similar fashion to Neronga's appearance in Ultraman R/B, Pagos' suit was freshly made for this appearance.
- Director Takanori Tsujimoto stated that Pagos' petrified body, which was seen throughout episode 12, was meant to show how people dealt with the bodies of monsters after they're defeated, since he rarely sees this kind of scene.
Powers and Weapons
- Burrowing: Pagos can burrow at moderate speeds.
- Energy Beam: Pagos can fire a yellow-colored energy beam from its mouth.
- Ultraman Taiga
- Strength: Pagos has great natural strength and exceeds Ultraman Titas's.
- Tough Hide: Pagos' exterior is tough enough for it to withstand attacks such as Hell Slash without taking any substantial damage.
- Energy Drill: A drill made of energy fired from its forehead, capable of going through buildings.
- Petrification: Pagos turns itself to stone upon death.