Fulajie'er's current form was born from the Deity Creation Project of the Ancient States. She belongs to the category of an incomplete "god," also known as a demigod or false god. The reason gods are considered as such is because they are much more powerful than ordinary people.
Now, the only thing that could bind Fulajie'er was the crystal in which her soul resided. If she had been able to evolve into a complete god, then she would have achieved true immortality.
The extent of a god's power need not be elaborated here. Gods can freely manipulate the magical atmosphere of the Otherworld for their own use and they do not die or age, thus being almost eternal.
Imagine if the Advance Team had failed to stop the mage from the Ancient States, who had tried to become a true god, the Otherworld would never know peace, and an evil god would have ruled all. Even the science of Earth would be powerless against him.