I think that Tobi is ten tails or jubbi..
Also if u think about it tobi mentioned that he gave nagato the rinnegan, which makes us wonder from where did he get the rinnegan? The answer is simple if u see the manga where the jubii has been shown, we can clearly see that its eye also has the same ripple pattern as the rinnegan. Hence it already had the rinnegan it merely transferred it to nagato in order to gain his trust.
Also if we see the actions performed by tobi/ten tails, we know that he manipulated the third mizukage and promptly eliminated almost the entire uzumaki clan whom he feared cuz they had very powerfull sealing techniques and uniquely strong chakra.
Later he with the help of itachi eliminated the entire uchiha clan because they possesed the sharingan which helped them perform very strong doujistsu and genjitsu, through which they can control other persons ( for example when sasuke used his sharingan to control manda).
Hence we can conclude that the ten tails was silently eliminating the threats which could oppose him.