ZECT are a military gear company formed to combat the invasive Worms that manufactures the Masked Rider Systems in Kamen Rider Kabuto.
However, the organization is later revealed to have been founded by the Natives in 1971 for the purpose of serving as a front for their agenda to convert all humans into Native Worms to achieve an "ideal peace". After most of the second wave Worms are exterminated, the Natives put their plans into motion, having ZECT's chairman Riku Kagami ousted so Mishima can take his place and distributing "Worm identification" pendants that actually convert their users into Native Worms.
In contrast to their mostly heroic role in the TV series, ZECT also serve as the main antagonists of the movie Kamen Rider Kabuto: God Speed Love, where in an alternate timeline they secretly form a pact with the Worms and construct the Jacob's ladder space station to allow the Next-Worms to invade.
ZECT's origins lie in 1971 after a meteor carrying the Native Worms crashed on Earth. The Natives warned of a second wave of Worms that would arrive 35 years later and formed ZECT with Riku Kagami and several others to manufacture the Masked Rider System to combat the second wave of Worms when they arrived.
At some point, ZECT kidnapped a young boy and imprisoned him in a compound at Area X, where the boy was subjected to a series of painful experiments by ZECT's second-in-command Masato Mishima that converted him into a Native transformed him into Kamen Rider Dark Kabuto.
Once the threat of the second wave Worms had been dealt with, the Natives put their plans into motion. Mishima, having formed a pact with the Natives, ousted Kagami as leader of ZECT and began distributing "Worm identification" pendants that would secretly convert their users into Natives. However, the plan was foiled by Kamen Riders Kabuto and Gatack, who defeated Mishima after he used the pendants to become the Gryllus Worm.
- Riku Kagami - Leader
- Masato Mishima - Second-in-command
- Arata Kagami
- Yuzuki Misaki
- Shuichi Tadokoro
- Renge Takatori
- Sou Yaguruma
- Shun Kageyama
- Shura Hokuto
Kamen Rider X
Kamen Rider Amazon
Kamen Rider Super-1
Kamen Rider ZX
Kamen Rider Black/RX
Kamen Rider Kuuga