Forget about the Brahmans; across the entire Empire, only the Uchiha Brahman is the Brahman, for he is the Supreme!
Kshatriya, Vaishya, Shudra.
Kshatriya.
This tier has nothing to do with one's personal abilities; it is strictly a matter of genetics. As everyone knows, chakra—this transcendental power—is a combination of spiritual and physical energy, a power that theoretically knows no limits.
Therefore, an individual's strength and total chakra reserve naturally depend heavily on their physical body and their genes.
Chapter 62