Rul-Ende (ルル＝エンデ), also known as the Root of All Existence (太古の理), is the final antagonist in Ys Seven.
Rul-Ende's nature is neither evil nor good, but of an eternal being that merely perpetuates the cycle of death and rebirth. As Ze-Kalios explained, the Root is merely the balance towards the Five Dragons of Altago. Where the dragons would sustain Altago through a balance of forces, the Root would return everything to nothing if this balance is ever upset. However, instead of having nothingness, the Root would then recreate all life and the balance in Altago once again, hence perpetuating the cycle all over again.
Rul-Ende appeared before Adol and company once they defeated the Maiden of Demise. Rul-Ende has three forms which employs all seven party members to defeat. The first two forms will each require two parties of three members selected randomly. Once those two forms are defeated, Adol must solo the final form alone.
With the Root of All Existence destroyed, the Wind of Destruction was stopped. Since the Root and the Five Dragons are but two sides of the same coin, the Dragon also soon departed. This brought the endless cycle of death and rebirth that persisted in the land of Altago since aeons ago to a close.