Duckula has numerous vampiric relatives all over the world, who are more classic vampires than Duckula, possessing fangs, red eyes and evil personalities. Only a small number, such as Don Diego, show any affinity or friendship toward the benign Count Duckula.

They come from many different countries, such as Spain and Scotland, and their costumes represent their native cultures. The relatives include Don Diego, a Spanish vampire duck who makes his fun and games by burning down villages, and Rory McDuckula, a Scottish vampire duck who later makes himself an enemy of Duckula

The most interesting exploration of relatives is in the episode "The Rest is History," where the current Count Duckula travels back in time using his castle clock to the year 1199 and meets the very first Count Duckula. The original Duckula was apparently a normal Count until his butler Igorth (possibly a relative of the current Igor) replaces a friendly pet bat with a vicious vampire bat, thus triggering the beginning of the vampire line. This makes Duckula's assertion that he is the 17th count a slight hiccup in the series as it is more likely he would be the 8th, if reincarnation can only occur once per century–unless there is some other means of regeneration other than the ritual detailed in the opening of each episode, or depending upon how the previous counts "died". This could possibly be forgiven, as the only time he mentions being the 17th count is in the episode "The Count and the Pauper," which was written by a guest writer