User blog comment:Xilinoc/Ch. 662 (not released at time of writing)/@comment-25897574-20160212090816/@comment-25897574-20160214023402

Maybe it was just for show? If she had one, wouldn't she be using it right now? This isn't the first time a shinigami achieved a high rank without one (Nanao). Heck, Tosen's Zanpakuto wasn't even technically his.