Ah, you've tapped into one of my favorite niche corners of the comics world. The blend of deeply-rooted Korean folklore with modern horror sensibilities creates stories that feel uniquely chilling because they're tied to a cultural memory of spirits, vengeful ghosts, and mountain deities. For finding these, I tend to look towards official webcomic platforms that have strong curation of Korean creators. WEBTOON's 'Canvas' section or their official horror originals are a solid starting point; you often find creators there weaving tales about the 'Gumiho' (the nine-tailed fox) with a terrifying twist, or stories centered on 'Dokkaebi' (mischievous goblins) that are far less playful than the legends suggest. Another fantastic resource is the app Tappytoon, which licenses a lot of Korean webcomics directly. They have a robust horror and fantasy section where I've stumbled upon series that use the 'Joseon' era as a backdrop for ghost stories, making the historical setting itself a character draped in shadow and tradition.
Don't overlook communities on Reddit, either. Subreddits dedicated to manhwa or webtoons often have threads where users specifically recommend folklore-horror blends. That's how I found a comic about a shamanic exorcist dealing with a 'Cheonyeo Gwishin' (a virgin ghost), which was steeped in ritualistic dread. The key is searching for terms like 'Korean folklore webtoon' or 'Goosebumps manhwa' alongside 'ghost'. Sometimes the best ones aren't the most prominently advertised, so diving into these fan-driven spaces can lead you to those hidden, chilling gems that perfectly marry the old tales with a pace and visual style that keeps you scrolling late into the night, maybe with an extra light on.