Kamen Rider 555

Kamen Rider 555 (officially "Masked Rider Φ's", also read "Kamen Rider Faiz" or "Phi's") is a Japanese tokusatsu television drama. It is the 13th installment in the Kamen Rider Series. It is a joint collaboration between Ishimori Productions and Toei, and was broadcast on TV Asahi from January 26, 2003, to January 18, 2004. It aired as a part of TV Asahi's 2003 Super Hero Time block, alongside "Bakuryū Sentai Abaranger".
Story.
The Smart Brain corporation, the world's most powerful corporation, is trying to take over the world using Orphnoch, the "next stage in humanity's evolution", to covertly kill off the human population. In pursuit of this, they develop three suits of power armor, called Rider Gears (each for Delta, Faiz, and Kaixa), to find and protect the Orphnoch King, who can fix a defect within Orphnoch DNA which causes their genetic structure to break down, leading to death.
The Rider Gears are stolen by Hanagata, the Goat Orphnoch and former chief of Smart Brain. He sends them to his foster children (dubbed the "Ryuseiji", after the school they attended) so they can stop the Orphnoch from achieving their goal. However, Rider Gears were designed to be worn by Orphnoch, and humans are unable to activate the systems without undergoing genetic generation.
A young loner, Takumi Inui, is unwittingly drawn into the conflict between the Orphnoch and humans and becomes Kamen Rider Faiz to save the life of Mari Sonada, one of the Ryuseiji. Smart Brain begins training him in an attempt to retrieve the Faiz Gear.
However, there is division amongst the Orphnoch, as those who wish to co-exist with humans rather than kill him, begin resisting the Smart Brain, who in turn targets them as well. Most of these "renegade" Orphnochs are either killed, remain neutral or begin siding with the Ryuseiji against the Smart Brain.
When the Tokyo police discover the Orphnoch are behind a series of bizarre murders, they begin operations to defeat the creatures, largely unaware of the various factions involved. They even begin performing experiments on captured Orphnoch in an attempt to find ways of destroying them, though this does not go well.
The Orphnoch King eventually awakens within a young boy named Teruo Suzuki, whom Naoya Kaido and Keitaro Kikuchi saved and befriended. Now, it is up to the holders of the Rider Gears to band together and fight for humanity's survival.