>>53589438Serena exists for the same reason Latias and Anabel and Angie exist: to introduced a temporary one-and-done love interest. None of these girls ever had any shot of getting with Ash for collectively the same reason, because a far more popular choice existed with Misty. And in Japan too, don't know why you think Serena and Amour is more popular than Misty and Poke there seeing as XY's viewership bombed in Japan and Misty got the final Ash shipping hints any girl will ever get.
Ash can have Paul and Trip and Alain and Gladion as rivals and they can get many more episodes of focus than his original rival got, but it doesn't matter because Gary will always be the character the vast majority of people think of as Ash's quintessential rival. Same thing with Misty and the rest of her "competition" if you can call it that.
