I personally like T'challa, the Black Panther. From his inception he was an intellectual and physical beast. A King of the most advanced country on Marvel Earth. His identity is publicly known and he doesn't give a shit what others thing, including the Avengers. In the beginning he had the physical attributes of Captain America with intellect on par with the likes of Reed Richards. Now he's the champion of the Panther God and his new abilities have yet to be explored. To see him in action, take a look at the outstanding work Christopher Priest did with the character. Amazing writing.