Shakespeare called it.... "The Green Sickness"
What is it?
Envy differs from its twin jealousy because it involves an awareness of an advantage enjoyed by another.
And accompany by a desire to have what they possess.
Why do I mention this?
Think about the character called your villain.....
What is it that they wish to possess but can't have?
Think about it.....Your next villain might just be an envious person.