But in that case, Shichika could not see how Soto the Twin had chosen anybody but the Itezoras.
The girl’s strength was monstrous.
Unparalleled – no other word sufficed.
Konayuki had thought nothing of carrying Shichika back to the cave.
And evidently, her monstrous strength was not unique to her, but shared by the entire Itezora family. In fact, Konayuki (still a child) said she was on the low end of the spectrum…
Thus, it would appear that Kiki Shikizaki had bestowed Soto the Twin upon the House of Itezora – no one else could handle the Twin, not in the entire world.
At least it was impossible for Shichika.
And thus impossible for Kanara Azekura.
Even Hakuhei Sabi, once the strongest swordsman in Japan, would have found the sword impossible to wield. However deft with Hakuto the Whisper, the most difficult sword to handle, he could not so much pick up Soto the Twin.
Even Meisai Tsuruga, to whom every sword was fair game, would have met her match against the Twin.
But not this girl – Konayuki Itezora held it like a stick.
As if the thing was not even remotely heavy.
Held it in one hand, ungracefully.
Horrifying.

Katanagatari Omnibus 2, Page 239