How do you get your brother to stop threatening you with martial arts?

How do you get your brother to stop threatening you with martial arts?
Talk to a responsible adult, such as your parents, and explain the problem you are having. If your brother is actively training at a Martial Art studio, the instructor should be made aware of his behavior. If the instructor is a good teacher, he/she will have a talk with your brother that might help. If the instructor is not willing or able to teach properly, then your brother should be removed from that school, and enrolled in one with a more qualified teacher.

If your brother is learning martial arts and he is threatening you, he is being taught in the wrong way. If taught in the right manner, martial arts will make you content and happy and you don't go around threatening people.