Err...my plot description was extremely vague.
And I got what you said about Dante. I was just trying to be funny I guess? /fail
Anyway, Blitz and Ruthiel aren't in love. Blitz doesn't fall in love with anyone in my story. Also, the time they spend together before Ruthiel gets captured is about three weeks. That's plenty of time to get to know someone, in my opinion.
Ruthiel asks Blitz to help her after she's saved because, well frankly, she WAS GOING to get close to him before killing him. A false sense of security? Back in Heaven, she was told that he was an abomination that needed to be killed. Because his power (the control over Darkness) was unknown and foreign to the Angels. They saw it as a threat to both them and humanity. So Ruthiel was sent to kill him. She tries numerous times to do so, but she ultimately fails and the attempts are unknown to Blitz. But as the weeks go on, Ruthiel begins to develop human emotions and realizes that Blitz is no abomination. He's a normal guy, despite his abilities. And THAT is why she gets taken back to Heaven. She's going to have her wings torn off for disregarding orders, and all that jazz.
On his way to rescue her, Blitz ends up in Hell. There the plot grows beyond Ruthiel. And that's all I'll give. I don't want to post spoilers. XD
And I don't find a "hero" using Darkness over used. In all honesty, Blitz isn't really a hero either. He's just doing what he thinks is right most of the time. It's true that he can't help but save someone in need, but I still don't think that makes him a hero. He does become one however, but that is WAY near the end of my novel.
The concept may sound generic from my horrible description, but trust me, it really isn't. Like any story, it starts off slow and then grows into something bigger. But thank you so much for all your thoughts and opinions! I really appreciate it.