Conversation so far:
How did Lord Voldemort's character begin?
In a 1999 interview, J. K. Rowling said Lord Voldemort was invented as a nemesis for Harry Potter, and she intentionally did not flesh out Voldemort's backstory at first.
Why did J. K. Rowling not flesh out Lord Voldemort's backstory at first?
Harry Potter didn't know he was a wizard so when the most evil wizard tries to curse him and it rebounds, leaving a scar, the evil wizard goes into hiding.
How else is Lord Voldemort's character developed?
In Harry Potter and the Deathly Hallows, a taboo spell is placed upon the name, such that Lord Voldemort or his followers may trace anyone who utters it.
What did Lord Voldemort do after placing a taboo spell upon his own name?
By placing a taboo spell, Lord Voldemort's followers eventually find and capture Harry and his friends Ron Weasley and Hermione Granger.
Can you tell me more about Lord Voldemort's curse?
Lord Voldemort tried to curse Harry but it didn't work and he's left with this lightning bolt shaped scar on his forehead and the curse rebounded upon the evil wizard.
What happens to the Lord Voldemort after he tries to curse Harry Potter?
The curse rebounded upon Lord Voldemort and he has to go into hiding.
Does anything else happen with Lord Voldemort in later books besides having to hide?
In the second book, J. K. Rowling establishes that Lord Voldemort hates non-pure-blood wizards, despite being a half-blood himself.

Question: how is he a bully?
Self-contained rewrite: How is Lord Voldemort a bully?