Digimon Adventure 02
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.
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.
The Digimon who are created by Control Spires all share the same goals as Arukenimon and Mummymon, which is to disrupt the balance of the Digital World, defeat the DigiDestined and allow both it and the Real World to fall under the clutches of evil. They are:
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.
The Dark Towers are the main feature of the Dark Tower Wasteland and inhibit normal digivolution within its confines. Dark Towers are also targetable enemies in the "Remove Dark Tower" series of quests given by Calumon (NPC) that are required to unlock certain Jogresses.