Right, the "30 Days" thing may disqualify this record. (But then we'd also have to apply this scrutiny to Anutrofho - her name got mentioned a bit before we see her true form, and her small statue even appeared way earlier.)
*Googles hibachi*
Incidentally, one line of dialogue I have in mind for her in the future mentions turning someone into minced meat. But now you make me actually reconsider to use a more East Asian culinary term instead...
Regarding her "sexy Halloween costume"outfit, BTW:
Clothes can be interchangeable (though she would probably consider this high heels to be rather impractical) - but what I would consider one of her key accessories (besides the katanas) is her wondrous sphere device that she is always wearing like a keychain.
Of course, firstly, I didn't yet come up with that back in "30 Days", and secondly, the keychain's, uh... chain is just barely visible in the comic page she appears in, so that's no big deal.
(Edit: On second thought thoug, this Anutrofho fan art, also by CG, is likewise a contender.) *
* Both this claims could actually be contested though. See CG's and my comments below.