Going off of the perfect Jin information in regards to Genjutsu
Madara or Itachi can effectively 1 shot Obito in his current form due to him not being able to break Tsukyomi or any High rank genjutsu. Normally Perfect jins can break out of genjutsu sort of like how Bee can with his partner. The only thing is since Obito and the Juubi are not actually partners but more so the Juubi is being controlled by Obito. If Obito is put into a Genjutsu the Juubi will not be willing to break him out of it.
Madara or Itachi can effectively 1 shot Obito in his current form due to him not being able to break Tsukyomi or any High rank genjutsu. Normally Perfect jins can break out of genjutsu sort of like how Bee can with his partner. The only thing is since Obito and the Juubi are not actually partners but more so the Juubi is being controlled by Obito. If Obito is put into a Genjutsu the Juubi will not be willing to break him out of it.