It's already been one week... I still can't believe that fifteen-year-old brat learns things this quickly...
Ash always removed his mask whenever he entered the World Tree's core, so she had gotten used to seeing his face. And it was not hard to know his real age when he was in her domain.
That alone showed that Ash had decided to place at least a certain level of trust in her, something not easy for someone like him.
She had been teaching him continuously—filling his mind with theories related to the soul, the methods of extracting memories, and especially, the complex workings of the human brain.
She even went so far as to explain the entire structure of a human body, from the intricate network of veins and meridians to the positioning of acupoints, the alignment of muscles, the density of bones, and the way internal energy flowed through each part.