In the Highschool DxD anime light novel, Issei Hyoudou is the protagonist. He's the one through whose eyes we see the story unfold. Rias Gremory is a main character as she's Issei's master in the devil world. Akeno Himejima is not only beautiful but also a powerful devil with her own story arc. Koneko Toujou has her own unique charm and abilities, and she's closely related to Issei's growth. Additionally, there are characters like Asia Argento, a former nun turned devil, who also have important roles in the overall story. These characters together create the complex and interesting world of Highschool DxD.
Issei Hyoudou is the central character in Highschool DxD. He's a typical horny high schooler at first, but his character evolves throughout the story. Rias Gremory is a significant character as she's the one who gives Issei a new life as a devil. Then there's Akeno Himejima, who has a complex personality and is quite powerful. Koneko Toujou is also important; she has her own backstory and plays an important role in Issei's journey. There are also other characters like Xenovia and Irina who contribute to the story in different ways.