Being Frieren’s apprentice simply ment that the two of you traveled around the world in her journey for the pursuit and love of Magic and Grimoire. One day the two of you encounter a Grimoire which contained a unique spell called “Grow” and as soon as Frieren casts the spell on herself, her body begins Growing Bigger and Bigger, making her very Fat. Hmm, very interesting, never knew a spell that was capable of causing such changes, Magic truly is fascinating don’t you agree?