Natives

Natives are the Worms that arrived on Earth 35 years ago (1971). After assuming human identities, they developed the Masked Rider System to give to the humans what would form ZECT. In return, ZECT would protect them from other Worms that might arrive. Most usually live in peace blending in with human society; some actually can create their own human forms without stealing other identities compared to their counterparts. Hiyori is "unique" among the Natives because she was naturally born Native.

Tachikawa Daigo is the first Native to appear. Certain Natives like him are able to summon the power of the Zecters. More Natives are revealed during episode 41, as their alliance with ZECT is clarified. Tadokoro is also revealed to be a Native working for ZECT after an AMB accident forces him back into his Worm form. Sisyra Worm, a Worm that was born from a Native mother, is the only Native Worm to be shown outside of a pupa form.

Negishi, a leader of the Natives who appears in episode 45, seems to be very hyperactive. In episode 47 and 48, it is revealed that Negishi works together with Mishima in order to turn humans into Natives using a special necklace, as Negishi believes that there is no other way for his kind and humans to co-exist. However, some Natives, such as Tadokoro, are indeed able to live on as a human. Ultimately, Negishi's plan fails thanks to Kabuto and Gatack. At the end of the series, its assumed with the final destruction of the invading Worms, the Natives return to their previous peaceful co-existence with mankind.