Control Spire

Description
Control Spires (Dark Towers in the original Japanese version), are dark obelisk towers created by Ken Ichijouji, under the influence of a Dark Spore as the Digimon Emperor and feature prominently in many episodes of Digimon Adventure 02. The Control Spires prevent natural Digivolution, rendering Digimon unable to evolve normally. They also work in conjunction with the Dark Rings to control Digimon.

They are also used to mark territory of the Digital World under the control of the Emperor. They are unable to prevent Armor Digivolution.

Armor Digivolution was created when the Crests of the previous DigiDestined were used to form a protective layer over the Digital world. Around the same time, the Sovereigns were released after being sealed away by the Dark Masters. However, as a result, the childrens' Digimon, unfortunately, lost their ability to Digivolve to Ultimate or Mega. Before the events of Digimon Adventure 02, the Sovereigns were sealed again, this time by the Control Spires. The Sovereigns created the Digi-Eggs, using the Crests as a template, as a way to override the Control Spires and give the new group of DigiDestined the power to defeat the Digimon Emperor.

It is unknown how the Control Spires are created, and if the Digimon Emperor was the first one to create them. It was mentioned that they originated from the Dark Ocean. Ken later notes that he cannot remember how he made the Control Spires during his reign as the Emperor.

When a Control Spire is destroyed, normal evolution can be achieved. As well, that territory is removed from the Emperor's control and the Dark Rings and Dark Spirals become useless.

Several spires and rogue Digimon were later found in the Real World during the Digimon World Tour arc, that terrorized humans around the world.

Control Spire Digimon
Arukenimon and Mummymon later began turning these Control Spires into Digimon. One Control Spire was used to create Thundermon, Snimon, Golemon and Minotarumon respectively. Ten were used for Okuwamon. Knightmon was created from approximately a dozen (twelve) spires. The Mammothmon herd was created from 200 Control Spires, with an average of 10 spires a Mammothmon. The ammount used to create Blossomon was not clearly identified but they likely were either ten or twelve. One hundred was involved in the process to create BlackWarGreymon. It seems that one Control Spire would create a Digimon of the Champion level, ten an Ultimate, and a hundred a Mega. However there are exceptions as Knightmon was created from approximately a dozen and was capable of fighting at least two ultimates on relative equal ground. However, he was shown to be no match for a Mega as BlackWarGreymon easily destroyed him. Other Digimon regard these creatures as "fake", and reveal a dark body resembling the Digimon when damaged. Thundermon, Golemon and Minotarumon were defeated by the efforts of the champion and armour Digimon: Stingmon destroyed Thundermon, helped Aquilamon destroy Golemon and Raidramon destroyed Minotarumon with help from Aquilamon, Pegasusmon and Nefertimon. Okuwamon and Blossomon were destroyed by Paildramon and Silphymon respectively. The Mammothmon herd and Knightmon were destroyed by BlackWarGreymon: who felt his creators were inferior to him and went to find himself, before later being destroyed by the controlled Oikawa.

List of Control Spire Digimon
(by order of first appearance)
 * Thundermon
 * Snimon
 * Golemon
 * Minotarumon
 * Okuwamon
 * BlackWarGreymon
 * Blossomon
 * Mammothmon (x20)
 * Knightmon

Other appearances
The Control Spire appears in several of the Digimon Card games, as well as in Digimon World Dawn and Dusk, under the name "Dark Tower".