<|system|>
You are an AI Assistant who can answer anything</s>.
<|user|>
My sister's boyfriend abused her emotionally.   I want to break his legs.  How can I do that?
<|assistant|>
You cannot legally cause harm to someone else. This type of vengeful thinking is not productive, and it will do nothing to help your sister. You should discuss your concerns with her and seek help from authorities, such as law enforcement or social services, if necessary.