What? An extremely ecchi-based series that actually has a decent plot line? Unheard of...
High School DxD (I guess Demon x Demon?) is like a cross between the fights of Ikkitousen and the setting Kore wa Zombie Desuka. An extremely perverted, girlfriend-less dude named Issei suddenly gets a girlfriend and then promptly dies soon afterwards. He is then reborn as a Demon and serves under high-class demon Rias Gremory.
The first line in the series after the initial intro are along the lines of "ah.. I wanna squeeze some boobs." You pretty much know exactly what you're getting into at that point. However, despite the very high level of ecchi (and surprisingly few god rays), this series actually manages to tell a relatively interesting story; though of course you have to be able to tolerate the amount of ecchi.
This is an above average series for the ecchi-based school-based genre that has decent action and your typical ecchi comedy. Do not watch if you cannot tolerate topless nudity.
So Issei apparently possesses a "Sacred Gear", some sort of magical weapon that is inside him (think Makens from Maken Ki). These Sacred Gear are important in the three-way war/battle between angels, fallen angels, and demons; and Issei is killed to prevent him from being a threat to any of the groups. Luckily for Issei, he is picked up by a high-class demon named Rias and suddenly is given a second chance at getting his Harem. Unfortunately he starts out as a weak, low-class demon and must train to become stronger.
The story can be divided into two main arcs that both have a good mix of rising action/climax/falling action. The first deals with Issei's induction as a demon and a fight with fallen angels. The second arc deals with Rias and her fiance demon. In general, both arcs are both interesting despite a fairly predictable progression.
This isn't a perfect work. Certain episodes felt like filler material, and the everyone-gets-sacrificed grand finale is way overused. There are also lots of elements that aren't totally explained (or are over-explained given their relative unimportance) but the series does set it self up for a season two and perhaps elements will be clearer then.
DxD is pretty good looking overall. The series overall has a slightly unsaturated look despite using some pretty strong reds and blue/purples. The series is not as crisp as it could be in some of the action sequences but I didn't notice it too much as the shiny bright attacks/effects obviously distract from the minor details.
Character styling is nice as well. You have a good mix of distinguishable primary characters, as well as a lot of plain yet differentiated background characters. I'm somewhat surprised at the level of non-censorship that AT-X gets away, I sure don't remember a high school club where all the girls occasionally go topless...
If you haven't gotten the message yet, this is an extremely perverse series, to a similar degree (though in a different way) as Sora no Otoshimono. There are multiple, highly suggestive scenes. This is not quite balanced out by occasional action, most of which involves Issei getting almost killed (again) before being saved by the other demons. As in Kore wa Zombie Desuka, the main male character has unusual regenerative abilities and the series takes advantage of this to bloody things up.
Assuming you can deal with the blood/boobs, this series is fairly good looking.
The OP is reminiscent of other girl-based fighting shows and the ED somehow reminds me of Infinite Stratos, both aren't anything remarkable but suitable for the series. The BGM is appropriate, I liked the stringed instrument parts, but is overall forgettable.
The VA cast is composed of surprisingly many veterans. Almost all the main and relevant supporting cast have very strong voice actors. Asia's VA is comparatively new but does a really good job in bringing out her personality.
If you take a look at the cast tab, you'll quickly deduce that this is a character-spamming series. There are at least two dozen characters that appear, take on a really minor role, and then quickly disappear never to be seen again. In general, I frown upon such a practice, but in this case the series successfully develops the main characters despite the extra baggage.
Issei is your typical hopelessly-ecchi guys who also happens to be nice and has an indomitable willpower (not too different from Zombie Desuka). He happens to then join a family of demons that apparently takes on the "Occult Club" role in the school. You have a good mix of character personalities ranging from cute moe/shy to ultra-sadistic.
Character relations are surprisingly well done considering the ecchi focus of the series. Many of the characters here are dynamic and change noticeably due to interactions with each other. Issei's relationships are probably best summed up as "it's complicated."
Overall Rating: (7.3/10)
The value of this series will greatly depend on your tolerance for ecchi. The story and character elements are fairly good for this genre and I found the overall progression enjoyable.