Originally Posted by NeoKakarott023
Oro's purpose isn't to kill/take Sasuke anymore, he's a sensor type. If he felt Naruto/Kyuub's chakra pass, then he felt Madara, Obito, and Jyuubs, and knows that even with Sasuke's body, that shit wouldn't be enough.
Orochimaru isn't a sensor type. He alone wasn't sensing Naruto's chakra. All four of them were and they were ONLY sensing him because it was so immense. Juubi's appears to be nature, which they can't sense. That's why Naruto entered Sage Mode to do so. Madara (his is non-expiring, not limitless) and Obito don't compare chakra wise.