I'm going to review this because it's become my favorite thing to read since Harry Potter. (It also chases away the memories of when I sat and read Twilight from start to finish. Alas those were dark days.)

Anyways...
I'm going to sum up the whole plot, in my own way, in just a few sentences, starting now:
Just how much insanity can you summon forth with a nipple, a dragon and a never-say-die attitude? Your answer would be 15 volumes and counting.
There's a lot of characters to introduce and so it gets off to a pretty slow start but when it hits full tilt you'll forget all about it being a Light Novel.

The art, I thought was actually really good, until we started getting less flaming demons and more loli upskirt pictures and other assorted hentai-borderline pictures but hey......

The characters of DxD come in huge quantity. Even so they don't feel underdeveloped, which I consider to be a pretty impressive feat. I speak as a author when I say it's extremely hard to juggle plot and character development at the same time. DxD features the sort of characters who would feature on polls as the greatest love pairing, the ultimate good guy or the biggest badass had they been written into Western novels.

Serious but silly, funny but sometimes dark, engrossing and entertaining.

Needless to say, I think you ought to read this....