Board Thread:New on Bleach Wiki/@comment-27120311-20151025235010/@comment-25801533-20151226193424

tensa zangetsu is the merger between his soul reaper powers (hollow ichicgo zangetsu) and his qunicy powers (old man zangetsu). The hollow is not a third entity that existed. the other visored seem to have a zanpakuto spirit and a hollow within them, however for ichigo his zanpakuto spirit and his hollow are the same being. I dont see the FGT training having anything to do with this.

His mask would form or save his life to protect him and itself. When he learned how to use the visored mask i think it was allowing him to access more of his true zanpakuto power than normal. This means his visored mask functioned totally different than the rest of them. Think of it like his normal state is the sealed zanpakuto and the mask is him accessing his shikai (bad analogy maybe).

They explained that after using the FGT that his powers were gone for good, but just like the quincy can have their abilities jumpstarted, the same thing was possible for ichigo (because he is a quincy). When a quincy exhausts his power it is sealed up inside them and must be reawakened (at least thats how I understood it). Urahara had suspicions that the same would apply to ichigo, but based on the amount of power he has they couldnt afford to try with only one captain level of power. so they pump in several captains and various lieutenants (some of whom were captain level but not captains) worth of power into a sword to jumpstart his abilities again.

this means his hollow/zanpakuto is still there and his quincy abilities are still there. both of which he later accepts as his zanpakuto spirit during the soul palace training.

when his zanpakuto is forged, he takes the ausachi and it becomes the hollow in appearance and just before the forging was complete he pumped in his spiritual pressure to the blades. Since his soul reaper powers are no longer being suppressed by old man zangetsu there would be no need for the mask as a power boost.

NOW, with all that said i think its likely that his bankai will include a mask as his bankai seems to alter his appearance and tensa zangetu has a mask. I also have a small theory about FGT and him using it again.... but thats for a different thread, or personal chat.