Spark Dolls

Spark Dolls (スパークドール, Supāku Dōru) are the transformed bodies of Ultras, monsters and Aliens from various universes.

Ultraman Ginga
Some time prior to the series, a multiversal war named the Dark Spark War raged between the side of good and the side of evil side, with the participants being comprised of the Ultramen versus the monster and aliens for the universe. Meanwhile, an Ultraman named Ginga fought a dark elusive figure and losing to it resulting all of the Ultramen monsters and aliens turned into figures known as Spark Dolls and became scattered throughout the universe. Though they were still alive but imprisoned as they became dormant and slumbered. Through some unknown means they fell to Earth in a meteor shower. Years later, Hikaru Raido found the Ginga Spark and the presence of this object caused the various Spark Dolls hidden around his hometown to being to activate. In response the Villain's lackey Alien Valky began going about giving Dark Dummy Spark to corrupt minded individuals to sow chaos on earth.

List of known spark dolls:
 * Ultraman Taro
 * Ultraman Ginga
 * Black King
 * Thunder Darambia
 * Kemur Man
 * King Pandon
 * Ragon
 * Doragoris
 * Ultraman Tiga
 * Alien Valky
 * Eleking

Trivia

 * The Spark Dolls are similar to the Ranger Keys of Kaizoku Sentai Gokaiger and the Rider Cards in Kamen Rider Decade.
 * They are similar to the Ranger Keys in that they hold the powers of the beings they resemble. Only in this case they are  the beings they represent.
 * They are similar to the Rider Cards, specifically in the movie Kamen Rider × Kamen Rider W &amp; Decade: Movie War 2010, End of Decade, in which they both were acquired when they defeat an opponent.
 * Another similarity with the Rider Cards is that they both have their own monster variations (Kaijin Ride Cards)
 * They are also similar to the rider cards of Kamen Rider Diend whom can summon holographic manifestations of riders.
 * The only known conscious Spark Doll appeared to be Ultraman Taro, however, Ginga spoke in Episode 6, revealing that he to was still conscious, which may be why Hikaru cannot transform at will.
 * They are the first transformation items to have a major toyline, as they replace the Ultra Monster Series and Ultra Hero Series.