2 random thoughts

[sage22]

Do you think tobirama ever sacrificed someone for edo?
How do you think minato perfected the reaper death seal without dying before obito's attack?

 

[ruinairas]

Tobirama does appear to be hinding some secrets and doesn't seem to have any interest in sharing "knowledge"....I think he has had some dark intensions.

 

[Ciao]

It would be sick if Tobirama revived Izuna.

 

[Form]

Were those really "random" thoughts?

 

[Twin Steps]

Beats me, just be patient and we'll hopefully find out

 

[avenged sevenfold]

I think he only created and when he knew the basics behind the technique he created he labelled it forbidden. after all it is forbidden for a reason. But who knows??

 

[Moss]

I believe Tobirama only used it in war; the fallen comrades/enemies were most likely used as sacrifices to bring more ninja back.