The Magi Supercomputer System is a set of three supercomputers in Neon Genesis Evangelion, designed by Akagi Naoko to run the myriad electronic systems of Nerv Headquarters. Each supercomputer is implanted with an artificial intelligence that is modelled after an aspect of Naoko's personality.
Other branches of Nerv around the world have their own Magi sets; the one specifically denoted by this tag is formally known as "Magi 01".