Does your character have blood?: Yes. Later, yes and kind of no (lol Grail mud).
Would their blood smell better or worse based on that Affinity: I would say at the moment it is better. He is ennui personified since he is always a little tired dealing with happy people since he wants them to be happy but also knows his happiness stems from their unhappiness. It leads to some exhausting feelings after while. As he becomes more Kirei, it is more indifference and being a trash pile so I dunno if that would taste good. Don't eat garbage, Elda.
Any other notable facts about their blood: Well, there is the eventual Grail mud. But also probably spicy as hell since he eats mapo tofu like it is going out of style.