@ShinAhSeiryuu That stinks. I think I thought up some ideas you could use, but you don't have to use them. Here are some:
-focus on the relationship between Crowley & Eos (like maybe involve another guy or girl to make Eos or Crowley jealous to make them slowly realize their feelings, or one of them is put in danger and the other had to save them, make some romantic scenes between them, things that make them realize their feelings, making them want to be together, stuff like that or etc.
-make enemies that try to start trouble or get in the way between them.
-make an enemy that will affect the world or the both of them.
-Maybe involve more characters
-you could involve more vampires for story plot or comic relief. Or You could involve the humans because Eos was really close with Guren and them. So like what would happen if they crossed paths because she's a vampire now.
Hopefully that helps! :) I hope you can keep writing you story because it's a pretty good story! :)