Two South Korean technology companies are borrowing from mobile gaming to shake up — and dominate — Japan's storied manga industry, a plot twist that has expanded the comics' fanbase to a new generation of readers.

Backed by tech giants Kakao Corp. and Naver Corp., Piccoma and Line Manga have become Japan's highest-grossing mobile apps outside of games. Such online manga platforms have seen a surge in popularity during the COVID-19 pandemic.

Piccoma's third-quarter transaction volumes more than tripled year on year to ¥11.6 billion ($110 million), extending a wave of online manga sales that has already seen digital surpass print in Japan's $5 billion manga industry.