the smurf are you guys talking about? She's famous because she died, yes, but she puts the cause and effect into main plotline for several of the events that happen. Meets Cloud, recruits him as her bodyguard. She's one of the ancient ones and is thus sought after. She gets kidnapped, Cloud has to go after her, and so on and so forth.

I'd say she's a pretty important part of the story. It's true that you don't realize how important she was until her death, but throughout the entire story leading up to it, she's pretty significant in a subtle way.