He was planning to use nagato, so nagato would use rinne tensei on madara, but nagato obito and madara
Because Nagato was an Uzumaki. That allowed him to use the eyes to a good potential.
Uhu, but Madara implanted senju cells in himself so he could use the rinnegan at the same level like Nagato did right?
No he need the senju cells to awaken the rinnegan. He implanted them after his battle with Hashirama but nothing happened for years and then finally when he was near death, it finally awakened. Nagato was perfect because of his background of being an Uzumaki, who are known to have special chakra and strong lifeforce.
Allright, so because Madara was near death when he awakened the rinnegan, it was useless to battle anyone because of his age?
And because Nagato has special chakra & a strong life-force its perfect to give him the rinnegan right?
I always wondered why he didn't just use Obito from the start.