Board Thread:Naruto Discussions/@comment-25409224-20140911175512/@comment-2005101-20140922164708

Tengai Shinsei was likely an application of Chibaku Tensei, fortified by Susanoō. There are two reasons I've come to this conclusion: Thus, while a Mangekyō Sharingan technique was used to supplement it, it was a Rinnegan power at its core.
 * The manner in which Madara, as the Jūbi Jinchūriki, used Chibaku Tensei to create that multitude of satellites against Naruto and Sasuke; hurling them upon the landscape in the same fashion.
 * And the reactions of those who saw Tengai Shinsei; exclaiming something along the lines of there being "many more", and "much bigger", if I remember correctly...

Limbo: Hengoku was also clearly said to be the true power of Madara's Rinnegan, so that most likely was not one of his Mangekyō Sharingan techniques. It's unfortunate, but Kishimoto left Madara and Izuna's dōryoku completely unknown, with the exception of Madara's Susanoō.