I came up with a theory about the shadow stealing.
Don't know if anyone else posted it before me so don't complain about copyright.
"I believe the shadows are used to fuel the corpses into reanimation.
Moria has the ability to steal shadows and use them to animate stuff.
Hogbak has the ability to make bodies from body parts.
Put those to together and you have undead.
And the exiting point in the arc will be when the zombies are asked to give back the shadows and thus die."
Sounds pretty logical.
too predictable.i believe some of us here have thought of this possibility before(including me).oda would have lost his touch if it turned out this way.