No Kids Zone

Doesn't every child dream of a world without grown-ups? But when a deadly virus wipes out everyone over the age of twenty, reality proves to be far more sinister than a childhood fantasy. By the time No-eul turns eight, he is already familiar with the virus and the mysterious monsters that roam the land. When his mother passes away and his village comes under threat, he sets out on a journey to find "Utopia," a rumored safe haven said to hold the cure for the virus. But this so-called "Utopia" may not be what it seems...

(Source: Webtoon Entertainment)