According to the
Danger Mouse episode in which he first appeared, Count Duckula was originally one of DM's villans. He frequently
terrorized the countryside and worked for
Baron Silas Greenback once or twice, but all he really wanted was to be on
TV. Danger Mouse couldn't allow this, as the
world would surely suffer after watching his
terrible acting.
Later, the show Count Duckula was formed, where the Count had a completely different attitude, described in the other writeups.