Whipping around to face Renji, Rukia punched him in the arm as hard as she could, which was a lot harder than most people her size could punch. "Don't get all high and--" She realized she was starting to yell, so brought her voice down to an angry hiss. "-mighty just because you can release Zabimaru's Bankai, Mr. Look-at-me-I'm-a-Big-Important-Vice Captain!" Really, she wasn't angry with him at all, but this was how things were with them.

Rukia's manner instantly changed as she turned back to the conversation, expression calm and attentive. "Ah, yes. Zanpakuto are our weapons. They take the form of katana, usually, but they aren't physical weapons. And most people can't see us because we don't have corporeal bodies. At least, not usually."