Board Thread:Theories and Speculation/@comment-28939725-20161201164545/@comment-734582-20161205094105

QuakingStar wrote: Obito is not better than Nagato with Rinnegan. I think you missed my point. Obito is better than nagato when he received that eye. In a few days, weeks at most, Obito was controlling 6 biju. His Six Paths technique was more advanced. He did a bunch of things. Nagato's first documented use of a Path is summoning Gedo when he was already in Akatsuki (ten-ish years later?). The rest of the paths he developed afterwards (since the Six Paths technique is a response to his immobility). We don't know how he took down a few mediocre ninja, for all we know he simply genjutsu'd them and cut them down.

Comparatively, Obito learned it a whole lot faster. He was also busy growing an army, developing the Ninjutsu to create his six paths (e.g double sealing Biju, creating the controlling chains, etc), etc. He simply may not have had time to learn to use all techniques. After all, he saw what awakening Susanoo did to Sasuke and may not have wanted to spend a day or more half-dead from the aftereffects, when his time was limited and precious. (Keep in mind, Kabuto didn't join until a day or two before the war. Until then, Obito was expecting to fight the entire thing himself, with 6 biju, his Paths and 100 000 zetsu). Kakashisologod wrote: You still havent answered my question,why not pull naruto and black receivere him in the head?(i know it wouldnt workt but why not try) There may be unknown side-effects to using this. For instance, i wonder if it prevents Obito from phasing, in which case it's simply not worth it. Alternatively, if Tsunade's counter to this technique works (which is really cheap and easy to do) then it may just be too pointless a technique to even bother to learn. Either way, Obito didn't bother, which suggests there's a good reason he didn't bother. I personally think he can't actively use Rinnegan techs and phase at the same time.

So a TLDR for all of this:

Obito learned the Rinnegan in a surprisingly little amount of time. Had he gotten more time to use it (decades like Nagato) he would've rivalled and probably outdone Nagato. But, just like other characters (Minato, EMS Sasuke) we never saw it because they died or transformed before they could manage the full potential.