The Age of Romance
You probably know that I am a mild supporter of the Sesshoumaru/Rin pairing. Yes, mild, I am not a fanatic and I'm still holding out on the idea that Sesshy is actually betrothed to some half human princess somewhere who can kick his butt (he needs it I tell you. A human who practically worships him isn't going to kick him into shaping up...), and I occasionally indulge in a bout of Kag/Sess fluff reading... but really, I think Sesshoumaru/Rin is a plausible coupling. I don't mind if others disagree - variety is the spice of life and all that jazz. What bothers me is that so many people reject the pairing based entirely on the age difference. I read a fanfic once that, while hilarious, really got off on that point making people who support the pairing sound stupid. I remember the author had Naraku say (as a joke) that once you reached a certain age you ceased to care if your lover was too young for you. And my only thought was - that shouldn't be a mocking comment, it's true! When you're two thousand years old everyone is so much younger than you are that it really doesn't matter. You'd never have a love interest if you waited for someone closer to your age to show up! And before the thought makes you sick, think of all the famous literary pairings with huge age differences. Aragorn and Arawen from Lord of the Rings, Cupid and Psyche in Greek mythology, Spock's parents in the original Star Trek! The reason these pairings seem "romantic" instead of disgusting is that we meet them after they are both adults and already involved. You don't have to think about the fact that when Psyche was born Cupid was centuries, if not millennia, old.
And if you won't accept my argument based on pure principle I'll give you a reason from the actual show that it is plausible and not crazy and sick. How many of you are Inupapa/Izayoi fans? Ever occur to you that if Sesshoumaru was 900 when Inuyasha was born that means his father was at least that old. In fact, I do believe that at some point I heard that Inutaisho was almost four thousand when he died. Since Izayoi was human, that means that he was nearly four millennia older than she was. And you can't deny that this is a canon coupling. And how about Jinenji's parents? You don't think that demon was way older than that young human girl? Old demons with young humans pops up all over Inuyasha!
How about Inuyasha and Kagome? Or even Inuyasha and Kikyou? Inuyasha was a hundred a fifty when he met Kikyou, two hundred when he met Kagome. And for those of you who speculate that he will still be alive in Kagome's time and will come find her (I know you're out there - I've read your fiction!) he'll be seven hundred by then! Yet none of you care that he loves a girl more than one hundred years younger than he is! And when you live such a long time one hundred years or a thousand years ... it's pretty much the same. I guess it comes down to being as old as you feel - or look. Who cares that Sesshoumaru's a thousand years old? He looks like he's nineteen! And pretty soon it will look like Rin is too old for him...
The point is, whether you actually think it would be decent or not there is plenty of evidence to support the fact that Rumiko Takahashi thinks it is. So don't knock the Sesshoumaru/Rin pairing over age difference. It just doesn't matter.