Fantasy YA/children's book about meeting a male creature who is one of the last of his kind, then later encountering a female counterpart

Question

I read a fantasy novel in grade school around 2007. I think it was a standalone novel, not part of a series.

What I remember is the main character(s) enter a fantasy world. I have the impression they were human children/teens and outsiders to the world. Early on they meet a creature who is one of the last of his kind - in fact he might have thought he was the very last of his kind. He wasn't human but I believe he was humanoid.

They journey together to some place/city; I'm pretty sure reaching that place was the key objective of the protagonists. They reach it near the end of the book, during which they encounter a female counterpart of the same species. The creature wants to court her and keep their kind alive, but he is shy to approach her. Our human protagonists give him encouragement.

Answer 1

I'm not sure that's the answer, but there is something somewhat like this in one of the Belgariad's books - Relg and Taiba, the Mother of the Race that Died.

But, for that matter, in Dark Crystal Jen the Gelfling believes he is the last of his people, then he meets Kira. He does travel to the city of the Skeksis, but he is alone, not in a group.