Enna saved Yuma Tsukumo after Eliphas destroyed the bridge he was running on, causing him to plummet to the abyss below. After Yuma woke up, Enna told him about the events that had been taking place in the Astral World.
According to Enna, the Barian World and Astral World were once one single world. It was during the time when "The Power of Chaos" existed in their world, thousands of years ago. The people of that dying world believed that they could Rank-Up if they just threw away "Chaos" from their world. Therefore, any soul with Chaos was banished from their world, eventually creating the Barian World.
Now, Astral World is a world were nothing bad exists, not even hatred. It is a pure, clean world, but without "The Power of Chaos", it gradually became weaker due to losing this power; Astral World has become a place that exists only due to Rank-Up, resulting in the creation of "Eliphas", the will of Astral World and a being whose only aim is to Rank-Up.
Enna told Yuma that he has the "The Power of Chaos" inside him. "The Power of Chaos" is the power of one's desire to live, the desire to protect others, the will to keep living, and the heart's ability to keep hoping. It is a force that drove primitive life to keep living. This is the reason why "Eliphas" was after him.
She asked Yuma to help the Astral World cure their illnesses with his "Power of Chaos" and save the Astral World from its eventual end with Astral's help. After Yuma left, Eliphas appeared to Enna and asked her if Yuma was here. Enna confirmed it and informed him that Yuma used the power of Chaos to heal the Astral residents and that Yuma will also use that power to save the world. Eliphas then left to confront Yuma himself.
After Yuma's and Astral's final Duel, Enna discussed the Astral World's new crisis with Eliphas.