This "sixth finger" mystery is interesting. It reminds me of some movies that are either similar to this plot or concept ......
Also remember to support the author.
Lol... now I know why it's familiar.
If you really enjoy the read, you should check out the live action on Netflix of this. This is why I thought this webtoon was familiar. It's a good movie to watch, if interested.
Svaha: The Sixth Finger