Review of High School DxD
This series is surprisingly decent in spite of its entry into the ecchi genre. While having the typical elements of ecchi like our perverted male lead Issei and a good amount of fan service and perverted content rear their head, High School DxD is smart enough not to use it to cover up a flimsy plot as this baby offers a good amount of exploration into its world and devoting focus on a number of characters among Rias and her servants among the Gremory family. Issei mixes around personality traits of a pervert and the hot-blooded main lead found within shounen battle anime. While helusts for and peeps on girls, he doesn't act on his impulses and cares for the well-being of the girls he interacts with among the Gremory residence enough where he puts himself at risk to protect them. These traits are nothing new for an anime with Issei, but the series strikes a balance with these aspects to his personality so neither one gets too overbearing and obnoxious with the worst sides of these common character types.
Outside of Issei, many of the characters in High School DxD within the series follow typical archetypes found within high school and action-type anime. Some of the characters do get some fleshing out with how they've been affected by the supernatural elements within the series such as Rias' family status with devils and Asia's equal acceptance of all types of beings making her face prejudice by those among her church. Otherwise, the majority of the cast are mostly underdeveloped and exist to fulfill the tropes they personify from high school and action-based anime, counting the irredeemable cocky and scumbag antagonists that the series introduces to create conflict in a couple arcs of the series.
The world exploration within the series serves to explore differing elements to the supernatural world of High School DxD. Outside of devils, the series introduces a number of other magical abilities and supernatural creatures that include familiars, magical teleportation, fallen angels and dragons. Elements to being a devil within the series are decently fleshed out such as how servants are created, their weaknesses and the influence of higher families within the devil world are explored.
The action element to the series dabbles a bit into shounen territory with how it is handled. Many of the abilities used by the characters in the series are nothing new that has been seen in anime such as Issei's Boosted Gear looking like a knockoff of Kazuma's Shell Bullet power from s-CRY-ed and Yuto's use of a ridiculous number of swords for battle being like what Archer and Gilgamesh utilize from Fate/stay night. Also, the typical tropes of said genre such as the male lead getting a power boost in the heat of battle and refusing to give up in spite of overwhelming odds, as well as a battle game style match being utilized in a later episode. In spite of these issues, the fights are decently animated and the animators do well at covering up any shortcuts they may have utilized to get what they needed out of action scenes.
Overall, High School DxD is a surprisingly decent offering for the ecchi genre as it mixes supernatural lore and action with its storytelling while offering the typical perverted antics of ecchi. It doesn't break any new ground and I wouldn't recommend this to those who detest the ecchi genre and/or shounen battle titles. But if you don't mind a series that dabbles into both elements without going too far in depicting them, then High School DxD may be for you.