User blog comment:Gilgamesh79/Highschool Dxd Timeline/@comment-31137559-20170820150619

April- Volume 1. Issei gets reincarnated into a devil. Everything else in Volume 1 happens.

End of April/Beginning of May- Volume 2

June/Beginning of July- Volume 3/Volume 4

Mid July-Mid August- Volume 5

September- Volume 6/Volume 7

October- Volume 9/Volume 10

November- Volume 11-Volume 16

December- Volume 17-18

January/early February- Volume 19-21

Late February-April- Volume 22

June- Volume 23

DX4- Somewhere after 23

July- Volume 24