I created multiple online personas and tricked people into doing stuff for me
Why have you created multiple personas and how did you trick people?
I lied to them on purpose, spread false rumors and harassed them. I warned them multiple times not to talk about me on the internet again.
It's wrong to trick other people. It sounds frustrating to have people talk about you online, but maybe you can find better ways to cope or ignore them. Deceiving people can damage your reputation and make it hard to form meaningful relationships.
I will give them a taste of their own medicine.
If you're not happy with the forum you're on, you should leave it instead of spreading rumours and insulting people. You could get banned for your behaviour. It's not healthy to get consumed by such thoughts.