|This article is about a/an concept in Kamen Rider W.|
Quarks (クオークス Kuōkusu) are psychic-powered soldiers created by Doctor Prospect, a scientist working for Foundation X, as his own personal army. To enforce his will upon the Quarks, Prospect assumed the form of the Eyes Dopant (アイズ・ドーパント Aizu Dōpanto), branding the Quarks with an eye marking on their foreheads that would kill them painfully should they try to escape. He also utilized barrier known as Heaven's Horn to weed out weaker Quarks within the complex and ensure they die a peaceful death. The strongest of Quarks would survive to continue training, while the weaker ones would be terminated. One of their tasks was to eliminate NEVER when Katsumi Daido and his forces invade to try and free them. With Mina, Katsumi managed to inspire the Quarks to rise up, leading them to a rebellion in which Prospect's elite loyal Quarks are killed attempting to stop the prisoners as they all escape. Unfortunately, the Quarks are all terminated by Doctor Prospect, leaving only Mina, who survived the termination unbeknownst to Katsumi.
- Jun Kazu (Foundation X's liason to Doctor Prospect, transformed into Kamen Rider Eternal (Red Flare) then the Utopia Dopant; first killed by Katsumi Daido as Kamen Rider Eternal, resurrected as Necro-Over before finally being killed by Kamen Rider Double CycloneJokerXtreme)
- Lloyd (bodyguard of Doctor Prospect; killed by Gozo Domoto during the Quark rebellion)
- Shion (bodyguard of Doctor Prospect; killed by Kyosui Izumi during the Quark rebellion)
- Mina (elite Quark; inspired the captive Quarks to rebel with Katsumi Daido before surviving termination)
- Riki (recruit; rebelled against the elite Quarks before being terminated)
- Cho-san (recruit; rebelled against the elite Quarks before being terminated)
- Nonko (recruit; rebelled against the elite Quarks before being terminated)
- The use of psychic soldiers was used again in Kamen Rider × Kamen Rider Wizard & Fourze: Movie War Ultimatum with the Monster League and psychics supplied by Kagehito Banba who, according to JK's, sources, was the one who sold the Quarks to Doctor Prospect in the first place.