Who

The idea is, of course, everyone. We all have the power to hurt one another, whether it be physically or verbally. On No Harm Day, you vow to hurt no one. That's it. It's simple.

Moreover, if you are someone in charge of people or responsible how other people treat others you will also promise to do everything in your power so that NO ONE suffers on that day. One single day of no killing, no hurting, no harming.