The Mysterious World of Mountains and Seas

There is such a kind of people on the Blue Star. They possess strange powers. Every country is gathering these people to form organizations and fight countless battles in secret. Little do they know that there is another more terrifying disaster on the Blue Star. This disaster occurred hundreds of years ago, but was prevented by a man. However, people in later generations found a text on a stone slab left by that man. The text above translated is "With this mountain and sea contract, I will summon you, the strange beasts of the mountains and seas that are proud of the gods in the world."