I would advice you to change your social circle (and maybe work) to deal with those people, who are more tolerable and will not hurt you for who you are. And break the bond to people, who want to hurt you because of your personality. So you will not have to be so afraid about discovering your anonymity anymore. But it's not so easy, so it's more an advice for the perspective.
For now... I think that the advice to deny your connection to your webtoon is reasonable. How your person in question will able to PROOF that that webtoon is yours, if you'll deny everything with enough certainty?