A fourth season of High School DxD is set to premiere some time in 2018 after the show's third season wrapped in 2015. The series is an adaptation of the 2008 light novel series from writer Ichiei Ishibumi and illustrator Miyama-Zero. However Studio TNK (School Days, Seven Mortal Sins) is passing the torch to Studio Passione (Rail Wars!, Rokka: Braves of the Six Flowers) and Yoshifumi Sueda will assume directing duties. The news was revealed at the Fantasia Bunko Festival 2017 last weekend in Akihabara, Japan.
Alternatively, the fourth season wll be titled High Scholl DxD Hero. The first (12 episode) season was succintly titled High School DxD and premiered in 2012 while season 2 was titled High School DxD New and ran for 12 episodes in 2013. Season 3 again consisted of 12 episodes and was known as High School DxD BorN and was released in 2015.
High school student Issei Hyoudou is your run-of-the-mill pervert who does nothing productive with his life, peeping on women and dreaming of having his own harem one day. Things seem to be looking up for Issei when a beautiful girl asks him out on a date, although she turns out to be a fallen angel who brutally kills him! However, he gets a second chance at life when beautiful senior student Rias Gremory, who is a top-class devil, revives him as her servant, recruiting Issei into the ranks of the school's Occult Research club.
Slowly adjusting to his new life, Issei must train and fight in order to survive in the violent world of angels and devils. Each new adventure leads to many hilarious (and risqué) moments with his new comrades, all the while keeping his new life a secret from his friends and family in High School DxD!