The Ultra Series (ウルトラシリーズ Urutora Shirīzu) is the collective name for all the shows produced by Tsuburaya Productions featuring Ultraman, his many brethren, and the myriad Ultra Monsters. The Ultra Series is one of the prominent tokusatsu superhero genre productions from Japan, along with Toei produced series Kamen Rider, Super Sentai, and the Metal Heroes. The Ultra franchise is also one of the most well known examples of the daikaiju (大怪獣, "huge monster") genre, which also includes Toho's Godzilla series, and Daiei Film's Gamera series. However, the Ultra Series also falls into the kyodai hīro (巨大ヒーロー, "Giant Hero") subgenre of Tokusatsu shows.
As revealed in Mega Monster Battle: Ultra Galaxy, the Ultramen are a technological advanced civilization who were originally identical to humans until they were evolved into their current state of being following the activation of the Plasma Spark which replaced their dead sun. Ultraman and his many kin are usually red-and-silver (although several color variations have been seen in recent years) and have glowing yellow almond-shaped dome eyes (although there are exceptions to both the shape and color) and various abilities, most notably to fire energy beams from various positions of crossed hands. They also share a strong cultural sense of justice and duty, a majority of Ultramen joining the Space Garrison (宇宙警備隊 Uchū Keibitai) to maintain peace of the universe from invaders and monsters.
The Ultramen that are sent to other worlds are given Color Timer, or "warning lights," which eventually begins to blink with increasing frequency if an Ultraman's energy supply dwindles or is mortally wound (and turns from blue to red). While on Earth, due to both human pollution and the atmosphere filtering out solar energy, an Ultraman can remain active on Earth for a limited span of minutes before their energy is depleted and they die. This forces an Ultraman to either assume a human form or merge with a human host body, the latter process have healing properties that include reviving a recently dead person with their own lifeforce.