After glancing at the old yellow bull that was now charging wildly, Leon turned his head back and continued to move towards the depths of the clouds and mist, still disguised as Fredri.
...
Because he always felt Fredri was not very trustworthy, several times he used the essence of origin to enhance Heart Lake's power but failed to see through her disguise. Only something more "concentrated" than the essence of origin might accomplish that, which could only be the essence of origin itself.
So if Evangelin's memory wasn't faulty, and the only person currently possessing the essence of origin amongst the ancestral remnants is Number 1, then Fredri must be one of Number 1's people.
Additionally, she managed to "snatch food from the tiger's mouth," secretly taking away two and a half portions of dream's origin from Leon and the Dream Resting Master. Hence, it's over ninety percent possible that she is Number 1's true identity.
