Porco and Reiner both, can't split them up. As for what made me fall in love with this guy, it was his sacrifice; his death was glorious, because it was selfless; then I worked my way back to his childhood and rediscovered the beauty of his character, which I see as flawless from the beginning until the end; it's not the lack of flaws that makes a perfect storyline, it's the flaws and faults that shape one into a wonder, especially in fiction, and that is how I see Porco -- as a small storyline that outshines many of the other more important ones. AoT is a huge world, with many individual stories within it, but few compare to Porco's and how complete and satisfying it is, from his childhood until his end, from a storytelling perspective.