RX-421DU The-Phi Gundam

The RX-421DU The-Phi Gundam (aka φ Gundam, Phi Gundam, Defy Gundam) is a Newtype-use Prototype Mobile Suit developed in secret by using the now-illegal  technology. It is the titular suit of Mobile Suit Gundam The Phi and is piloted by Maboroshi Nou.

Development
Around UC.0094, a year after the end of and after Anaheim Electronics's acquisition of Psycoframe from Neo Zeon, the company began to test with the properties of it over the next few years. Phi Gundam came into development when a Federation Corps known as Lotus Eater commissioned a Gundam-type Mobile Suit which utilized Psycoframe but could be controlled by any pilot, along with the Omnicron Gundam (Ο Gundam).

After UC.0096 and the, the Federation publicly outlaws Psycoframe due to its dangerous nature. However, Lotus Eater still insisted on the development of the Phi and Omnicron and forced the project team working on the two mobile suits to move shop from the Moon to the Earth in a far off and remote peninsula for the sake of secrecy.

Trivia

 * Phi (Φ/ϕ) is the twenty-first letter in the Greek alphabet. In the system of Greek numerals, it has a value of 500.