Let me just elaborate using a tangible example.

A Legacy Written In Blood. This is a mystery/horror RP I'm doing right now.

Samuel Blithe is the main character of this story, hands down, no contest.

But wait... Samuel Blithe doesn't even appear until like 10 posts in. O_o And we start off with this Owen guy, and his girlfriend Allison.

Weird, huh? Downright fucked up! If Samuel Blithe is without a doubt the central character focus, shouldn't he be in the very first post, killing someone, seducing a girl, or asserting his dominance and presence somehow?

No, because Owen is also a VERY important character, with an amazing, very rewarding journey within this story.

Then there's Lucavi! Haha!!! You won't even know who Lucavi is until a long way into the story. But Lucavi is probably the second most important character in this story. He's also extremely powerful, on a social, political, and physical level. He's a representative of The Order, which means he basically cannot be fucked with, unless you're stupid, or suicidal and too cowardly to do it yourself.

Is Lucavi a god-mod character? No, despite what newbs may think, he's a necessary antagonist force. Interestingly enough, Lucavi turns out to be more of a neutral, almost protagonist role.

See, Sam is a member of the Drakul Covenant in Blackwater, which are friends with the neighboring Fletcher Covenant in New Haven. Gabriel Fletcher (Master of the Fletcher Covenant) is killed, and Sam is framed for the murder.

This provokes Adrian Fletcher, son of Gabriel, to declare war on the Drakul camp.

When this happens, Lucavi shows up looking for Sam.

So with all of this shit going on, how oh how could you [i]possibly[/i] fit a character of [i]any[/i] importance into that?

Well what about Allison, Owen's (ex)girlfriend, (ex by now because Alison and Owen broke up, and now Alison and Sam are together) who by the time the second story starts, has become the most powerful character in the story.

Or Elizabeth May Drakul, eldest daughter of Vlad Drakul.

Or Alucard Drakul, only son of Vlad Drakul.

Hell, Vlad himself!!! He's not very present in the story, but he's one hell of a role! The man behind the myth, The Impaler himself!

Or Hunter & Calib, who were behind the killing of Gabriel Fletcher all along, and now plan to rise from the shadows of the wilderness and wage war on the now weakened Covenants.

Or Michael Lancaster and Wyland McRae, who are hired by The Order to "liquidate" the entire Drakul Covenant after things get really messy toward the end of the first story...

Then there's one of my favorites, Preacher. Literally a fly on the wall, yet one of the most engrossing, interesting, rewarding characters I've ever made...

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There's no excuse for not being able to fit a good, important character into a plot, regardless of what's been established, who's who, and what's what.

I could STILL fit more characters into Legacy. That's why there are at least 2 more RP's after Rising.