Mu Mu Mu

Every 10,000 years, a Heavenly Demon—a legendary master of the Demonic Cult—is born. But the modern era has two geniuses: Hoya, a boy with a burning interest in martial arts but no inner power, and Soma, the disciple of the Mad Demon who wiped out the Murim Alliance in a single day. When fate brings them together, Hoya decides to learn everything he can from Soma, but Soma only wants Hoya's help in figuring out the password to his master's well-stocked bank account. Who will claim the title of Heavenly Demon, and will they remain friends or become rivals?

(Source: Webtoon Entertainment)