I love those two and their relationship, it's probably my favourite one in the series.
Well, what can I say, the artwork is beautiful. I like the cold colors with some warmer ones added here and there and eyes and... everything, honestly. I like how bandages are an important part of the background. They really help with adding depth to the picture.
Yukine, my precious, you're looking good there~
Oh, and I think the titles are just fine! I mean, Yato
is pretty simple but I think it works really well with your Yaboku
artwork. And since they are in contrast with each other, it's a good match. You know, something like.... Past vs Present?