Tem Ray was an engineer working with the Earth Federation on the V Project, a military armaments plan to create the Federation's first prototype Mobile Suits. Born on Earth and previously married to Kamaria Ray, Tem left his wife and moved with his son Amuro to Side 7, a space colony which also served as a secret base for the Federation. There, he began working on the design and construction of the Federation's prototype Mobile Suits and was to oversee their transport to Earth.
However, the Principality of Zeon learned of the Mobile Suits within Side 7, and a small team was sent to destroy the Mobile Suits before they could be loaded aboard the White Base carrier. In the ensuing chaos and evacuation of the colony, Tem's son commandeered the second Gundam unit constructed in the colony and fought the Zeon's Zakus. The resulting explosion caused by one of the Zakus' reactors being destroyed blew a large hole in the body of the colony, and Tem, unequipped for extended time in outer space, was sucked out into the vacuum, apparently to his death.
Tem Ray managed to survive the accident and was taken to the neutral colony of Side 6; however, the extended period of time he was in space led him to suffer from oxygen deprivation, wrecking his mind and leaving him delusional and prone to mood swings. When Amuro meets his father on Side 6, he congratulates his son on a job well done and gives him a piece of circuitry that he claims would drastically increase the Gundam's power; however, Amuro recognized it as nothing more than a useless piece of junk.
Tem's final fate is left ambiguous—In the TV series: he watches the battle just outside of Side 6's space and celebrates his creation's victory over Zeon forces. In the third compilation film, he celebrates then stumbles head-first down the stairwell that lead to his apartment. It's unknown whether the fall kills him or simply knocks him out.
- In the PS2/PSP version of Gihren no Yabou (Threat of Axis V) Tem Ray establishes his own faction in a what-if campaign, composed entirely of engineers and scientists. The faction is able to build every single mobile suit (as a combination of Tem Ray's genius and the various scientists) in the game, including a unique unit, the Gundam Tem Ray Custom, but is heavily set-back by a lack of good pilots.
- Many games play on Tem Ray's helplessness in the field of science and mobile suit development since his mental deterioration:
- The piece of junk he built actually appears in the PlayStation game Super Robot Wars Alpha and many other strategy-type Gundam games, however it usually has a negative effect on the stats of the mobile suit that equips it. In Super Robot Wars Alpha, this item, called "Tem Ray's Circuit", gives the equipped unit a penalty to mobility but reduces the repair cost of the unit if it is destroyed to nearly nothing.
- In Dynasty Warriors Gundam, Tem Ray is one of the scientists who can give you upgrades for your unit. However, all of his upgrades only raise stats about 1-3 points, compared to the 10-20 points others give you.
- In Dynasty Warriors Gundam Reborn, he appears in the "Develop the Legendary Plan Upgrade" as the proprietor of the search, which required 100 plans. However, once given the plans, the supposed upgrade he develops appears far older than the modern plans and is suspected to be defective. He similarly appears in the DLC mission "1 Suit, 10,000 Enemies" where having survived the One Year War in this mission's story, he gives another of his defective circuits to Zeta-era Amuro. In the mission's end scene, Tem watches Amuro and his Gundam's battle on TV and celebrates the Gundam's power, the Federation's might and what he believes was his circuit's usefulness, little knowing that neither Amuro nor the Federation ever bothered using it.
- In SD Gundam: Scad Hammers, he's obsessed with the Gundam Hammer and ignores every other weapon when developing the RX-78-2 Gundam. Ironically, this results in him managing to safely escape from Side 7 on the White Base. His relationship with Amuro is also portrayed in comical manner, a crazy scientist and a rebellious son.
- ↑ Mobile Suit Gundam: Gihren no Yabou