I like RyuuxUta the most because their situation is so interesting and intense.
But when it comes to the best male character in this manga, Yahiro is the one, no doubt. He is fun to be with and really loving.
Well... maybe saying u wont give up might force her to push u away instead. His behavior also feels like comes and goes when he acts like a lil kid in contrast of when hes talking to Ryuu