Why didnt Tobirama stop Edo-Tensei?

[Aze]

Orochimaru was in full controll.

Orochimaru could not take the risk , of letting Tobirama roam free , since he could have released Hashirama out of Edo Tensei aswell , most likely.

Somehow I still think , that Tobirama knew alot more about Edo Tensei than Oro or Kabuto for some reason.

I think , that Oro and Kabuto only improved the "Edo Tensei Tag Kunai" to remove their mind and make them killing machines or something.

 

[sgt]

If he wasnt under full control why Orochimaru needet the kunai to get him under control?

they werent fully revived, they were gaining their true form slowly so orochimaru had time to put the kunais in their head. By that time it was already to late.. It's like a newborn baby they need time to get used to this world, thus reviving the dead was taking its time on 1st and 2nd to get to their true selves.