Greeza

"If there was a space energy reading of zero, then there's nothing in front of Space Musketty. Literally nothing, I mean. Zero, a void. That light show is our senses trying to perceive a total lack of information."

- Guruman as he depicting Greeza's first form.

Greeza (グリーザ) is an alien from Ultraman X. A demonic monster that wanders the universe destroying all planets that give off biological signals, Greeza is the strongest enemy that X faces during the show's run. Greeza was a destructive being that targeted the life forms that were the most abundant in life energy from planets, and then left nothing in his wake, according to Ultraman X.

Subtitle: Void Monster (虚空怪獣)

Past
"Greeza targets the life energy of planets, and leaves nothing in its wake. After Greeza destroyed three planets rich with life, I followed him to this solar system. When Greeza sets his sights on Earth, I was only able to defeat him by pushing him to the sun. It all happened fifteen years ago."

- Ultraman X, A Beautiful Ending

Fifteen years ago, after he destroyed three planets filled with life, Greeza desired to destroy the solar system. As he raced into the Milky Way, he met resistance in the form of Ultraman X. Both Ultra and the figure clashed each others in their travel sphere forms until they reached the sun, where X takes this opportunity to throw the villain into it. However, this had become his greatest undoing, as the villain's demise had set forth the event of Ultra Flare, with said wave trapped X in a form of computer data and banished him to the Earth.

Present
"Come on, haven't you heard about this? One day, black lightning bolts began to strike this planet. Any monster they hit will go berserk, like they're being driven to destroy anything." "Do you know what the Dark Thunder Energy is?" "I'm sorry but I'm not that well-informed. But at this rate, your planet will be doomed. I've got it on good authority."

- Dada and Daichi Ozora during the former's confession.

Greeza had in fact survived his supposed destruction, revived from the waves of Ultra Flare and launched the Dark Thunder Energy on Earth to turn monsters berserk and has been doing it for at least 18 days, starting at around Mercury, and then moving past Venus to reach the Earth, according to the UNVER HQ at Geneva. His activities were notified by aliens hiding on the Earth, so much so that a Dada predicted that the Earth shall face extinction from the attack. To make this worse, the lightning was also being taken advantage by an evil faction during its debut, until they were defeated.

Sometime after a group Bugbuzuns' intrusion to Earth, Mamoru and Wataru spotted Greeza in his first form when they were flying past the moon and it's contact made the Space Musketty lose contact with headquarters. Greeza eventually landed on Earth and completely obliterated the UNVER base in Nevada and absorbed all of the Spark Dolls there because it sensed that place as the largest source of Spark Dolls in the world and that Earth's monsters are the most abundant in life energy. Greeza then turned into his second form and flew straight to the second largest source, which just so happened to be the Xio headquarters in Japan.

On his way to Japan, he is met by opposition by Xio USA in the North Pacific airspace and they launch Perseus missiles at Greeza, but he dodges them all and destroys the resistance. He then zooms in on the Xio base when Daichi turns into Ultraman X and he turns into his Exceed X form immediately to stop him. After a quick tussle, X is joined by Hayato in the Sky Musketty and Cyber Gomora to stop Greeza, but the alien gains the upper hand due to his distortion, shielding, and strong attacks. Eventually he downs the Sky Musketty with his beam, and unrealizes Cyber Gomora with his vortex, which also interfered with the electricty in the surrounding area as well. X tried to use the Exceed X-Slash on Greeza, but he absorbed him. Unfortunately for Greeza, this lead to his mistake as he was presumably killed as X blew him up from within.

Soon afterwards, Greeza regenerated and re-enact his attack on the Xio base and was met with resistance by Cyber Gomora again. Greeza quickly made work of him and, at the same time, destroyed the Xio base with his energy attacks. The alien then absorbed all of the Spark Dolls at the base, even the recently revived EX Red King, Tsurugi Demaaga, and EX Gomora, until he transformed into his final form. Then, Greeza resumed his rampage on Earth despite the obstacle of Xio. Before he could finish them off, Wataru and Mamoru returned in the Space Musketty and destroyed the energy ball meant for Xio.

Soon enough, Daichi and X reunited and stood in Greeza's way once more. Even in his Exceed X form, the Ultraman couldn't keep up Greeza and his new powers gained from the Spark Dolls, including Gomora's Super Oscillatory Wave and EX Red King's Flame Road, but then Daichi reached out to Gomora and struck Greeza in the chest, resulting in all of the Spark Dolls he absorbed coming to X and he united with him to form the Hybrid Armor. Greeza was eventually defeated once and for all with the Ultimate Xanadium, powered by all of the Cyber Cards and Spark Dolls.

Trivia

 * The prop of Greeza's first form was recycled from the Purana in Neo Ultra Q.
 * Greeza's second form's unstable movement was due to its nature being "nonexistent" and a walking space anomaly, therefore its existance is an instability to itself and its surroundings. Said movement was inspired from butoh, a form of Japanese dance theatre that encompasses a diverse range of activities, techniques and motivations for dance, performance, or movement.
 * Kiyotaka Taguchi, revealed that before Ultraman Exceed X sacrificed himself to blow up Greeza from within, his Xlugger provided Greeza a physical body. Once Greeza reconstituted from its apparent destruction, it was no longer a space anomaly and therefore he physically existed. However, this was also a primary factor to his fall, as Greeza's current state allowed the Xlugger to finish him.
 * Greeza's name comes from words Greed and Glee.
 * Greeza's name is similar to Frieza, one of the main antagonists in the Dragonball franchise (Greeza (グリーザ) is simply one kana away from Frieza (フリーザ)).
 * Similarly, the color for Frieza's Ki (Energy) is purple, and Greeza's travel ball emits the same color.
 * While his nature of targeting other life forms to feed and grow is similar to Cell, another Dragonball villain.
 * One of the series' writers, Hirotoshi Kobayashi, said that a motif in Greeza's design was his own traumatic image of Zetton when he was a child.
 * Another writer, Takano Nakano, has stated that Greeza's final form with its spike armor was inspired from the Sagrada Família church.
 * The final form's suit was simply the second form equipped with a jacket-like prop and a pair of gauntlets to make up his talons. Said prop however was too bulky and heavy for the suit actor to handle, thus not much physical movements were made by Greeza during the recording.
 * Out of all Cyber Cards, Greeza is the first to have its Cyber Power rated full.
 * In Xio's database display, his categorization was defined as "TYPE UNKNOWN". Despite his given subtitle "Void Monster", his Cyber Card set is categorized as "Type A (Alien)".
 * The way how Greeza in his Final Form, roars in different voice when he is utilizing the Spark Doll powers is similar to Ultraman Ginga Strium and Ginga Victory, where they emit different grunt sounds of Ultras when using the Ultra powers.
 * The power of his Dark Thunder Energy is similar to that of the Chaos Organism, as both are able to mutate monsters, and cause even peaceful monsters to go on a rampage. The differences are;
 * Chaos Organisms turns monsters into "Chaos" versions of themselves.
 * Greeza evolves its victims into their strongest forms. Should said victims didn't have one, it simply gives them new powers instead.