Law of Devil

On the continent of Roland, heroes rise; magic apprentices confront the gods. On this magical continent, prophecy foretells the collapse of the Roland Empire's millennia-long prosperity, but a chosen one will, like Aragorn, the founding emperor of the empire a thousand years ago, turn the tide. Dewey, the eldest son of Count Dulei, the Imperial General, is physically weak and sent back to the Roland Plains by his family. He accidentally crash-lands on a deserted island, makes a deal with a demon servant, and gains boundless power, thus beginning a legendary journey to becoming a king...

(Source: Tencent, translated)