Nova is the last boss in the Mega Drive version of Raiden Trad.
Details
Nova is a large UFO-shaped vessel. When approaching the boss a flying capsule will appear from the bottom and shoot in the player's direction, eventually attaching itself to the UFO and activating it. It moves around the top of the screen, continually dropping debris at the player while its four antennas shoot bullet spreads. Once the antennas are destroyed it will begin shooting from the front.