I bear no favorites in initial, though there are many in which I very much enjoy, perhaps above others:
Itachi - Due to his character, personality, and background, the revelation of his story and sacrifices for Sasuke and the Hidden Leaf had been beautifully constructed.
Nagato - His origins far exceeded many in the aspect of troubles within one's childhood, on the verge of starvation for months, watching his parents be murdered before his eyes, caught amidst the hell of war, branded with the ideals to bring peace with the world only to become corrupted by hardship and misery. Despite his brief appearance, I enjoy him though there had been far more potential for him in the series within my perspective.
Many more ^..^;;