User blog comment:B214/Don't ask about season 4/@comment-86.199.208.148-20160703232037/@comment-26345952-20160703233830

Though HS DxD is in a manga, it is not the original source material, it is only another adaptation. High School DxD is a Light Novel and if you want to campare the diferences from last season please read from Vol 5 until Vol 7, and if you like it keep on reading.

You can find the english translated novels in the page Baka-tsuki.com, the last Volume is on hold for now but you can Read the first few chapters on zxzxzx-blog.