Aoko Aozaki, unlike her sister Touko, became the Aozaki heir, leading to a strained relationship between them. Touko, shocked at this development, murdered their grandfather and fled to the Association. Aoko led a life of wandering, while Touko excelled as a magus and became renowned as the world's greatest puppet master. Touko's initial hatred for Aoko stemmed from her obsession with reaching the Swirl of the Root.