I remember really liking this anime in my teenage years, but as I've grown older & matured, I've grown to resent this anime, therefore why I've given it a 5/10 and why I haven't seen Season 4.
I will get to the positives thou, as there are some:
- Story concept is really interesting and how all the mythologies are used in the show, and in the novels (which I haven't read).
- Character Designs
- Rias Gremory, I just really like her characterization, at least when it comes to serious situations
- Yuuto Kiba
- Fight Scenes
- Anime Openings are pretty great, just, don't watch the first 2...its better to listen to them
And now, to the negatives:
- Issei Hyoudou
- The Ecchi/Hentai aspects of it
- Filler as from what I've heard, there is some towards the end of Season 3