The best meat
In order to treat his soul wounds first, Robin spent the rest of his days inside the prisoners' tent searching for new ideas.
He spends a large part of his day trying to devise a technique to take advantage of the massive thundercloud within his Soul Domain in order to heal his soul as quickly as possible, but his injuries prevent him from fully concentrating...
After every hour he spent searching, she had to rest himself from thinking for another two hours, and even in these two hours he did not sleep or sit in meditation, but spent them dissecting the buds...
After two and a half months have passed since arriving in Greenland, Robin was finally able to modify the Soul Replenishing Technique into a technique that combines cultivation and treatment... And he called it the Soul Filling Technique.