Alright, I am going to mention a couple of things in this thread. If they have all already been mentioned before then I am very sorry. However,
1st- Tobi and obito are both the same laters in the name
2nd- both of them have an orange theme and as tobi wears his mask Obito wore goggles.
now this gets a little more complex here..Regardless of whether tobi is obito or not this is huge in my opinion.
-Kakashi's mangekyou has the ability to collapse space and trasport things to another location by focusing on one spot. Considering this jutsu is restricted to kakashi's sharingan, which belongs to OBITO, means that tobi is either obito, or possesses obito's eye because both kakashi's and tobi's sharingan use the "focus one spot to collapse time" effect, which tobi uses to transport himself. Which means the original owner probably can use other spacetime effects, like how tobi becomes intangible.
Now to me that makes a hell of a lot of sense..and it would make sense for whoever Tobi is to have come and taken Obito's eye when he died because Kakashi only took one. I realize this is definitely only a theory and probably has some holes in it because it is near impossible to guess the full truth when it is unknown. but yeah!xd
Sarutobi could be Tobi as well based on letters
