User blog comment:Gary299/High School DxD BorN episode 4 review/@comment-74.173.162.168-20150430171322/@comment-24910433-20150430180251

Well they ended S1 with Issei and Rias kissing. S2 with everyone moving in, so I guess ending S3 with Issei and Rias getting engaged makes sense. And then we all know how S4 will end.