“Did you say – she wiped out the Itezoras?” she asked. “How on earth did she manage that? Am I correct this was before the sister acquited Akuto the Eel?”
“Indeed – which only goes to show it’s not the Mutant Blade that makes her such a monster. As I mentioend, she has also mastered many of the ninpo stylings of the Maniwa –“
“In which case, we can assume that she has taken on the tactics of the Sacred Guardians of Mt. Shirei, and the swordplay of the warrior monks of Gokenji Temple… Fighting only makes her stronger. She doesn’t even need to lift a finger – with those eyes.”

Katanagatari Omnibus 3, Page 35