First of all I think that Ichigo has two stages to transform when he has his Vaizard mask on. When he is a Vaizard he represents a hollow. We all know that arrancars have a release form, they have their almost looking human form and when they released they transform into some kind of animal or beast. For example Grim=Panther, Nnoi=mantis, Ulquiorra=bat. Now on chapter 222 Ichigo has transformed into a Lizard watch:
Now that picture represents that he took the form of an Adjuchas. That is his first form.
His second release form would be the form of a Vasto Lorde and the outfit of an Espada member. His second release form is none other than, Hichigo or Shirosaki (however you wanna call him), he represents a Vasto Lorde and an Espada, in his clothing that is white, and the appearance of almost a human being with a little hollow touch. Watch here:
That picture represents the form of a vasto lorde and the outfit of an Espada member. This would be his second and last form.
Is a possibility. The First release is the form of an adjuchas, remember they symbolize animals and Ichigo is a Lizard in this form. His second release is the form of a Vasto Lorde and Espada, they suppose to symbolize a human, so the Hichigo/Shirosaki from the inner world would be prefect. For me it has logic.
In the recent chapters of Bleach we saw Ulquiorra having two stages or transformations, that means that powerful hollows can have more than one release form, and on chapter 349 we see Ichigo transforming, into the lizard hollow form. I highly doubt that, that would be his only form of a hollow, we all know that his inner hollow is to damn powerful and we all know that Hichigo/Shirosaki is not gonna stay as a Lizard, he will break out and take the form of Hichigo/Shirosaki, the one we have seen on Ichigo's inner world. Take for example an arrancar, when his mask is remove or broken they take a humanoid appearance. This example shows why the lizard form can brake and take the second form:
The difference is that the one coming out from that first form will be Hichigo/Shirosaki but with out the vaizard mask on, and transformed in his second and last form.
-Vasto Lorde in Japanese means= Great king of the hollows
Does this ring a bell, Hichigo/Shirosaki is always saying to Ichigo the stuff about the king and the horse. This is a clue
. Hichigo/Shirosaki probably
wants to be the king of all hollows, and that's why he wants to get out and become the King and Ichigo the horse.
Now will that happen on the fight between Ulquiorra and Ichigo, I don't know for sure, but I am almost sure that this theory will occur. This can take place on the Ulquiorra battle or in a future battle.
I think that this theory can occur, what do you think?