This character only appears in the El-Hazard Radio program, which takes place
after the first OVA series.
Myuun is an ancient presence from several millennia in the past. She appears to others as a young girl, but in reality she is a manifestation of the souls of the ancient El-Hazardians who died in the great wars that destroyed the ancient civilizations. She wants nothing more than to destroy El-Hazard so that the mistakes of the past cannot be revisited.
She does this by taking possession of others' bodies to do her work. In the series, she possesses Fujisawa and uses his body to get past an the defenses of an ancient device that serves to restore El-Hazard (Please see Salli for more information.)
She was defeated when Makoto stopped her plans for destroying the device when Makoto synchronized with the machine and prevented its destruction.