|What's needed: appearances, other spire digimon|
Digimon Adventure 02
Under the influence of a Dark Spore, Ken Ichijouji became the Digimon Emperor and began building Control Spires across the eastern Digital World. According to Ken, the Control Spires originated from the Dark Ocean, but after renouncing his role as the Digimon Emperor, he could not recall how he actually made them. The Emperor built the Control Spires in order to prevent natural Digivolution and provide power to the Dark Rings that allow him to enslave most Digimon, and as long as a Control Spire stood in a sector, it was effectively under the Emperor's control. Unbeknownst to him, he had been building the Control Spires under the influence of Arukenimon, Mummymon, and the Myotismon-possessed Oikawa, as the Control Spires' true purpose was to imprison the Four Harmonious Ones and disrupt the boundary between the Human and Digital World so that Myotismon could return and conquer it. In response, the Four Harmonious Ones created the Digi-Eggs using the Crests as templates, so that their chosen Digimon would have the power to stop the Digimon Emperor.
After Ken Ichijouji gave up his Digimon Emperor persona and stopped building Control Spires, Arukenimon begins using her "Spirit Needle" technique to transform the remaining Control Spires into soulless puppets in the shape of various Digimon. Despite this, BlackWarGreymon, who was created from one hundred Control Spires, developed a soul and rebelled against his creators, feeling that they were inferior to him. He went to find himself, but was eventually destroyed by Oikawa.
Later, after the DigiDestined successfully turned BlackWarGreymon away from destroying the Destiny Stones, Arukenimon and Mummymon took their plotting to the Real World to began building Control Spires there and releasing wild Digimon. These Control Spires can not prevent natural digivolution nor power Dark Rings, and are only used to distort the boundary between the worlds.
Digimon World Dawn and Dusk
The Dark Tower is a Farm Good.