Clue: Aristocrat to avoid: awful cad with allure regularly lacking (7)
Answer: DRACULA
Explanation: Definition: Aristocrat to avoid
In crosswordese, 'regularly' normally means "every other letter", but that is not what the word actually says, and not what is required in this case: an anagram ('awful') of 'cad' plus 'al[l]ur[e]' minus every third letter ('regularly lacking'); for the blood-drinking Count.