[duckonomy]

I'm not really sure what the "most popular" webtoons among non-Koreans. I know some American friends who showed me some that were supposedly popular, but I couldn't recognize.

That's certainly not a trend in mainstream webtoons, which are usually the Naver Webtoons. Nearly all (can't think of any one based on something) of them on that platform are original content. Sometimes they get published as novels. Like Noblesse.

I think the particular one you mentioned is based on a webnovel (similar to webtoons but novels).

I definitely see this trend in Japanese mangas though.