@radical_number6
... All the routes have the same beginning, so all that affirmation is plainly, without logical. Alternate universe didn't work that way you say. Shirou react at Saber first appareance exactly at the
same way in all the routes.
I said it, Shirou first behaviour is rather obvious. That's all. Other things are only, fag. Shirou fell in love in Saber seeing her in the ground various times, because he didn't want to saw a girl suffering like that, but also, he loves her determination. And that's all because he saw her past. He never saw Rin in that situation. In other routes he didn't saw nothing and nothing happen, because the route take another way. And when he
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saw Sakura in a similar situation, he really moves his ass by himself to save her, and that's because he notice his hidden feelings and act in consequence. That means, giving up everything he has always dreamed about, basically destroying himself for her sake.
That's the whole reason why Sakura didn't appear in the other routes that much. She is a plot machine. So if she isn't in the war, Shirou can develop other relationships to the point of forgot this. Since he doesn't take care of himself, he doesn't actually word it and at the end, she forgot even without notice it. That's how HF works. Is a way to say to the reader "Oh, so Shirou have own feelings since the beginning aside Kiritsugu ones. Even if he is 'void', at the end he is faithful to that feelings".
Archer is also another plot machine, but works in another way. He depends of being or not slashed.
For Saber (Rin too) first start more like an infatuation, that evolve to true love, of course. But is true too that Saber really shocked a lot Shirou, because that is obvious to in the other routes as well if you are a bit tenacious.