Board Thread:Versus Debates/@comment-26998824-20150927013622/@comment-26773508-20151101081552

Thekillman wrote: No genjutsu specialist has fought against a Rinnegan user. Unless we're now categorizing Tobi and Sasuke as Genjutsu specialists, which they clearly are not. It's far more likely that the people with Genjutsu simply considered it not useful enough, or their Genjutsu not strong enough.

Before someone says "sasuke vs Tailed Beasts", the Sharingan is pretty much the key to the Biju locker. Sasuke clearly is not a genjutsu specialist, as you've pointed out. However, Obito's position is more debatable. Lest we forget, he put Yagura in a Koto-like genjutsu for years and years and we still don't know how he did it. That feat puts him at Shisui's level. On the other hand, Obito has never been shown to use ultra-haxx genjutsus in any of his fights in the manga so far. So I can't help but suspect that Obito somehow came to possess a nameless Uchiha's Mangekyo that had Koto-like powers. And like Shisui's Kotoamatsukami, maybe there was a limit to how much it could be used, which may explain why Obito hasn't been shown controlling anyone else like that. Then again, Obito's Hashi implants should have counteracted the limitations of the hypothetical MS.

All in all, it's a very far-fetched theory and unlikely to be true. But my point is that our current info on Obito doesn't shed a clear light on Obito's true genjutsu abilities. So the question of his genjutsu expertise is an ambiguous one.