Board Thread:General Discussion/@comment-3354691-20160713191809/@comment-29422890-20170913233258

Yeah, its probably less something along the lines of 'Only the Espada can use Gran Rey Cero because its their own unique Cero' and probably more along the lines of 'Only the Espada can use Gran Rey Cero because they are the only Hollows with enough power to actually use such a powerful attack'. I mean, the Espada are forbidden from actually using it while in Las Noches because its supposed to be powerful enough to completely level a fortress. Ichigo being able to use Gran Rey Cero isn't that surprising, he's shown the ability to be able to use Cero when fully Hollowfied, even capable of firing one that was roughly the same strength, if not stronger, than Ulquiorra's Cero Oscuras. The only reason we never see Ichigo use Cero when he isn't berserk as a Hollow is most likely because any time he has his mask on before and after we see his fully Hollowfied form, he's scared of losing control and drawing more Hollow powers from the mask would probably make him slip even further. That, and firing a Cero is probably very similar to using Kido, which Ichigo has never been able to do, so the Gran Rey Cero is probably the only Cero he can actually do because it has less control required, and needs a LOT of power to back it up.

I dunno, something like that.