But the series first made a splash as a webcomic tailored to handheld screens.

In South Korea, so-called 'webtoons' are a pop culture phenomenon drawn and designed with smartphones in mind.

They've been booming for years, partly thanks to local tech giants like Naver and Kakao.

Cartoonist Choi Gyu-seok is the co-creator of the 'Hellbound' webtoon.

"It's a format in which you can read one episode in three minutes while waiting for your friend or during your commute, so we must captivate our readers in a very short amount of time. Hence, almost every scene must contain elements that can capture the reader's attention while keeping a rapid (storytelling) pace."

Choi says there's more room in the medium for experimentation.

Creators work an average of nearly 11 hours a day, six days a week.

It's a grinding schedule that means a webtoon concept can take as little as one week to go from the storyboard straight to the market.

Series usually come with weekly updates, meaning that creators can feed off of immediate audience reactions and respond in real time,

Reflecting ongoing trends or attempting more ambitious subject material.

Now with streaming studio in the mix, the payoff for creators can be huge.

Hongjaca is the mastermind behind "Dr. Brain," another hit webtoon that got snapped up and adapted for Apple TV+.

"Now, streaming services have made possible the inflow of new readers globally and more investment (in our industry), so they are asking for bigger ideas."

Naver's global webtoon business has seen its monthly active users grow by over 20 million in the past three years.

A Naver executive also noted international users far outweighed those in South Korea.