Universal soul is one of the main Keystone of the philosophy and the thought of the Upanishad. Brahma satyam Jagat Mitya Jeevo Bramanah Parah talks about the impermenance of the body and its existence.
Rajadhiraja was a great warrior. He always led from the front standing shoulder to shoulder with his men on front lines and earned the title of Jayamkonda Chola which means the victorious Chola King.
Nagarjuna was also termed as the Indian Einstein. He proposed the Theory of Relativity in his time in the form of a Sutra which is also called as the Prajna Parimata Sutra. He was a great patron of Mahayana doctrine.