Conversation so far:
Can you provide me with a little information on Harry Potter and the Half-Blood Prince?
Voldemort does not appear in Harry Potter and the Half-Blood Prince, although his presence and actions are felt.
What was Lord Voldemort like in his youth?
Riddle was outwardly a model student, but was in reality a psychopath who took sadistic pleasure in using his powers to harm and control people.

Question: Was he successful in doing so?
Self-contained rewrite: Was Lord Voldemort successful in having Death Eaters attack Hogwarts?