Obvious Answer
Deep within Mae's body was a Body Realm potential that was still waiting to burst through.
It had to be remembered that the Dream Asuras weren't just descendants of the Dream Wraiths. Mae in particular had the blood of Fire Giants and Horned Devils within her.
Together, this gave her both astonishing flame control abilities and a powerful body.
That had mostly been suppressed by her Dream Wraith characteristics because it was the most prominent of her Bloodlines. However, they were still there.
It was this Horned Devil Bloodline that was the most intriguing.
Horned Devils were pure monsters of power. Their bodies held a shocking amount of strength, and their Bloodlines held the secret to turning Nether Qi from a useful Mental Realm booster to a Body Realm one.