Please do not harass or hate on the person in question. For what they did is fundamentally wrong, and might have set forth a foundation to such encounters in the future, please do not be rude towards them while tackling this issue.

Fight or flight is human nature. And the OP for now has chosen the latter. But give them time to process it. To understand what they did wrong. DM and understand their POV and tell them why it is wrong.

Reporting will not solve this. All you are doing is taking them off the face of the internet, with no actual confirmation that the person won't do it again.

Talk to them, tell them why it was wrong. Even though you feel there is no logical POV for this, let them speak.

And then you explain why it is wrong. Why it is dangerous and what kind of a mindset it sets forth for the people in the fandom.

There is a fine line between education and harassment. Please do not cross it. Be diplomatic. Be civil. Be calm.

What you say today will not only affect the fandom's reputation, but also affect TwoSet's reputation on what kind of a fandom they have built.

Please be civil. You do not want to hurt the ones you are trying to protect.