People who frequently claim things as fact, when in reality they actually have no idea. Like Havok.
I clicked it with pleasure.
BTW
Shinobu is a name given to her by Oshino, her real name is :
Kiss-shot Acerola-orion Heart-under-blade.
キスショット・アセロラオリオン・ハートアンダーブレード
She wields no weapon.
And do you know why he named her Shinobu? Because the kanji, 忍, is written with the radical for heart (心) under the radical for blade (刀). Heart under blade.
As for the sword, no you never actually see it, but it's mentioned many times. For example, when discussing how to deal with Kanbaru's arm. Something about how if they got Shinobu to chop it off with her sword, Kanbaru wouldn't even feel a thing because it's so sharp - I can't remember exactly.