Definitely As Nodt. Oh man, I remember that after I read Chapter 570 I just broke down, literally. I can honestly say that he was, and possibly always will be my favourite all-time Bleach character, and Quincy of all time. I felt that his backstory lacked many details, and instead of it being a closure to his character, opened up more speculation and questions.
First of all, what really happened to the lower part of his face? Did Yhwach punish him? Did it happen because, possibly, the power that Yhwach gave Nodt consumed him to the point that it deteriorated his handsome facial features? What happened to his eyes and why did they turn black? Was it because of the reason stated above? Was the reason he was in the hospital because of the Quincy purge?
So many questions left unanswered. I really wanted to see him fight at least two fights in the final battle, and I personally felt like he had so much more to offer. He was one of the very rare Bleach characters that is unique in so many ways, and gets killed off in a span of approximately ten chapters..