>>258835396Suguha is one of the few to whom I'll grant the title of honorary sister.
She's related by blood as close as you can be without being a sister (cousin), and they were raised as siblings without knowing until much later (Kirito's parents died, his aunt / Sugu's mom raised him).
To top it off, when she found out (he found out earlier) he was already in Aincrad and so she was already in an emotionally vulnerable state making the reveal all the more impactful.
The only kicker is, as much as I'm an incestfag, I'm also a SAOfag and Asuna just works better with Kirito.
Although Yuuki still best girl and the fact he killed her off is still heartbreaking (though she survives in game canon).
Actually, for as much (unwarranted desu) shit SAO gets, it's sure not afraid to dish out some heavy hits.