C98 Art Duo Group

It's worth noting that even Kaguya, the progenitor of Chakra, only managed to unlock a single Nine-Tomoe Samsara Sharingan on her forehead, using it as a third eye.

As for Madara, he was born with the Samsara Eye and later absorbed Kaguya's incarnation, the God Tree. The eye he awakened was, in fact, Kaguya's.

Throughout history, only Kaguya reached the evolutionary pinnacle of the Sharingan