Board Thread:General Discussion/@comment-27110495-20160107181326/@comment-25383931-20160512165445

Well,i have a theory. We have already seen that Grimmjow has developed some power-ups on his own(Pantera's claws on unreleased state),and he may have developed a segunda etapa too. But,since Grimmjow had a trash Resureccion(compared to his unreleased state),i really dont think that a segunda etapa would be a huge power-up.

So,what's gonna make Grimmjow a Schulzstaffel-level fighter? Urahara may have assisted Grimmjow for it.Using the Hougyoku,Urahara,in order to gain Grimmjow's help,he made him a complete hollow-shinigami hybrid.

It may sound weird and unrealistic,but it has its chances. After killing Sternritter J,Grimmjow had his sword on Urahara's throat.Apparently,Urahara and Grimmjow had a battle between themselves,and probably Grimmjow gave a hard try on Urahara,enough to convince Urahara that Grimmjow was worth to trust with,and enough to convince Grimmjow that Urahara is as strong as Aizen.

Also,considering Orihime and Chad were there,Grimmjow understood that Urahara was on Kurosaki's part,and he needed a great power-up,in order to agree help Urahara.Finally,Grimmjow may understood that with his current powers,he couldnt beat and kill Kurosaki.Anyway,he was "watching" (with reiatsu),how Ichigo beat Ulquiorra,and how much superior did Ichigo's Reiatsu get,and he was informed by Urahara that he beat Aizen.

For all these reasons,Urahara,in order to get Grimmjow's help,he made him a complete hollow-shinigami hybrid,just like Tosen. Grimmjow,while being in Hueco Mundo after Urahara's contract,he was training with Urahara and Yoruichi,to master his new powers,together with Neliel and Fullbringers(as shown on manga)