User blog comment:Lemursrule/BLEACH 366 Review: Goodbye for Now/@comment-387500-20120327195345/@comment-1351982-20120328172628

First we do not know how exactly a physical Zanpakuto is born, aside from Ichigo. We don't know how one manifests theirs Zanpkuto in the academy, so it is possible that one can gain an Zanpakuto outside the acemdy. Kenpachi had a blade before his Captaincy, wether or not that was a Zanpakuto we have no idea. It may be possible to manifest a Zanpakuto without going the academy first, but again that is speculation.