Subtitle: Alien Silver (銀星人 Gin Seijin)
- Height: 180 cm
- Weight: 200 kg
- Origin: Space
One day, Yapool grew furious after having almost all of his Chojus becoming failures. He hired an alien named Space Mask and sent him to Earth. TAC at first dismissed his arrival, doubted it as a falling comet until an injured eyewitness reported that a figure arrived from the meteor and attacked the latter. At night, Space Mask infiltrated TAC headquarters but quickly chased by the officers and stowed motorcycle for escaping. While he was tailed by officers Yamanaka and Mikawa on a patrol car, Space Mask used his physic power to push their car into a nearby cliff. Yamanaka survived the fall but Mikawa died. Space Mask brought her lifeless body to a nearby hospital and revived her. Under his human alias Jiro Sakai (坂井青年 Sakai Jiro), Space Mask worked in an kindergarten and was visited by TAC a week later. Here, Sakai constructed the kids to create a Choju sculpture. Sakai quietly injured Hokuto's leg with his physic power when the latter sensed something suspicious on him. TAC officers also felt something suspicious on Sakai, since he happened to be on the accident a week ago and wearing a same bracelet with the alien infiltrator. To further investigate, they sent Mikawa to give him a scanner disguised in a charm, all while unknowingly watched by the alien. Nonetheless, Sakai willingly let himself unmasked by TAC, brought Black Satan to life and ordered it to rampage through the city. Ultraman Ace and TAC were having a hard time battling it until Ace seemingly killed it, only for Space Mask to revive it again. It seemed as though Ace had finally met his match but soon Space Mask was shot off a building and killed by Mikawa. Black Satan would soon be destroyed by Ace after TAC killed Space Mask.
- Actor: Tomiotto Tomikawa
- It is possible that Space Mask's bracelet contains similar technology to what Yapool uses to create Choju, as Space Mask uses it to create Black Satan.
- The episode's narration mentioned him to be one of Yapool's many forms, yet the 1984 magazine describe him to be an alien agent hired by Yapool, as shown above.
Powers and Weapons
- Flash Travel: Space Mask can incase himself in a comet for transportation method.
- Human Disguise: Space Mask can disguise himself as a human to blend in with the society.
- Controller Bracelet: Space Mask possessed a bracelet that can materialise any object into Choju as seen when creating Black Satan. But if the bracelet is destroyed, Black Satan will be rendered masterless and weak.
- Firecracker: Space Mask can create a small spark that strong enough to incinerate a hole in a metallic fence.
- Extraordinary Jumper: Despite his body being mentioned composed from extraterrestial metal, but Space Mask can effortlessly jump extremely high.
- Physic Powers: Space Mask can control certain objects with his mind, as shown able to sway a car into a cliff.
- Mechanical Stuffed Dog: Space Mask had an automated machine gun that disguised as a stuffed puppy. He also used this to infiltrate TAC headquarters.
- Healing: Space Mask can heal humans, even reviving the ones that recently died.
|Ultraman Ace Kaiju & Seijin|
|Verokron | Yapool | Chameleking | Vakishim | Garan | Aribunta | Giron Man | Brocken | Alien Metron Jr. | Doragory | Muruchi II | Gammas | Zaigon | Alien Antira | Unitang | Sabotendar | Baraba | Ace Killer | King Crab | Cattle God | Cowra | She-Devil | Hotarunga | Black Pigeon | Android Couple | King Kappa | Zemistlar | Aprasar | Aprasar Fairy | Space Mask | Black Satan | Giant Yapool | Mazaron Man | Yojo | Mazarius | Alien Orion | Sphinx | Alien Hipporito | Lunaticks | Undergroundmon | Gitagitanga | Red Jack | Baktari | Coakes | Bad Baalon | Kaiteigagan | Dreamgillas | Soundgillar | Machless | Snowgiran | Namahage | Alien Fire | Firemons | Alien Steal | Kaimanda | Shishigoran | Iceron | Woo II | Fubugirara | Onidevil | Gasgegon | Daidarahoshi | Hanzagiran | Verokron II | Yapool Woman | Univerlages | Aquarius | Alien Revole | Signalion | Geegon | Alien Simon | Jumbo King|