@obsoletezero: Are you sure about the translation of page 3's first speech bubble? Because it implies a ridiculously accelerated rate of growth from infancy to adulthood.
Hmm... I've seen a lot of comments about it, and it seems like a lot are confused with "couple of years" with the context of "2 years later".
In the raw it's 十数年後 would literally be "Tens of years later." or can be "Ten years later" (which doesn't make sense, because that would make the guy 10 years old if I put that.)
The context here is that "a lot of years have passed."
@obsoletezero because "a couple of years" literally mean 2 years, it's not context dependent, it can only mean 2 years, for it to mean more than 2 years it would have to be "couples of years"
but I think you should change it to "decades later" or "years later"
@obsoletezero: Plugging 十数 as a whole into a few online JP-to-EN dictionaries that I know of give me "ten-odd" and "several decades" as perfectly serviceable translations. I'd go with the former, since the guy looks like a teenager (i.e. 13-19) rather than an adult (i.e. into his 20s).
@Kobitohime
While yes, a couple of years does literally mean 2 years, in common english usage a couple can mean anywhere from 2 to 9, although higher numbers are less common. The important thing about it is that the number is indeterminate, otherwise the speaker would just say two.