Cultivating to be Legendary

Cultivating to be Legendary summary:

Qingyu Luo, a normal high school student, traveled to a nameless magic island due to an accident. It was said that hundred years ago, a legendary figure came to the island and successfully promoted to the demon realm. This legendary figure not only left behind a bunch of useful scrolls and treasures but also has four excellent disciples, who are still on the island protecting the treasures left behind...