Obito left the cage after he perfected his space time jutsu...
You're wrong.
Madara said both can't leave that place with their current
bodys, that means Obito could not leave in the state he was in, now pay attention to
page 15, the Zetsu on the
right looks more like a
Zetsu-Suit to me (there is a hole on the left arm side and probably also for the legs as well). Obito is using that
Zetsu-Suit = Tobi.
That explains these things
His height:
- He was about the same height as Minato, pretty much adult size, Zetsus are adult size.
Loosing his arms: (LEFT is Obitos "human" side, RIGHT is the one that got pretty much replaced with "Hashirama's DNA").
-
First arm injury: His LEFT arm dripped off when Minato hit him with a Rasengan, Zetsu Goo
AND blood came out of that sleeve = Obitos left side = Human.
-
Second arm inury: He ripped his RIGHT arm off after it got infected by Torune, that was just Zetsu Goo = Obitos right side = Hashirama DNA.
-
Third arm injury: He lost his RIGHT arm against Konan, it was also just Zetsu Goo = Obitos right side = Hashirama DNA.
Why his Sharingan is activated all the time:
- His right side got replaced with Hashirama DNA thus his Sharingan can't be deactivated hence it's not an Uchiha body on that side where his Sharingan is.
There you go, simple and easy no overthinking needed.