User blog comment:B214/Volume 22 spoilers/@comment-29778526-20170126060633/@comment-24941352-20170127223901

@Fandom-User

I guess time doesn´t count inside the barrier

And the Quote from Issei in Volume 7

"“Yeah, it seems like my life has been taken away quite a lot by the thing called [Juggernaut Drive]. I heard that I would be in danger at this rate.” 

[At this rate you won’t live longer than 100 years.]

''After the sports festival I was told that by Sensei. When I was unconscious, Sensei talked to Ddraig regarding my body.''

''Even if it was incomplete, due to the effect of [Juggernaut Drive] my lifespan was shortened drastically and I was finally told that I won’t live more than 100 years. In the battle from earlier, my life as a devil was shortened very much.''

''A hundred years would be plenty for humans but it is very short for devils. Buchou heard that and……she was crying afterwards. I couldn’t let Asia hear it. If she finds that out after we promised to stay together forever, I could see her falling into despair.''

''I was told that I would die if I go into that form, whether incomplete or perfect. After I was told that, my face remained pale for a while.''

''I was shocked. What was more shocking was that I would have to part ways with my comrades after 100 years and I was very saddened by that fact.''

''Well, it might be weird for a brat in his teens to talk about whether he was living more than 100 years or not. But when I had 10,000 years more to live and was suddenly told that I won’t live more than 100 years, the shock I received was huge.''

''I have only been a devil for about half a year, and that means I used up 99% of my life span you know? The shock I felt can’t be expressed in words. If it trimmed my life-span by a bit, then I would be fine but this time I wasn’t.''

If I only have 100 years to live, then I won’t be able to fulfill my dream of getting a promotion and becoming a Harem-king."