Ties that Bind: The Anchor NPC

For my upcoming Eberron campaign, I've asked each of the players to detail an "anchor NPC". This is a non-player character who has some in-built connection to the relevant PC, and who has some reason to attend the same party as the PC at the start of the campaign.

(It should be noted that "some in-built connection" is deliberately vague, as is "some reason to attend". The NPC could be a friend, relative or lover of the PC, or s/he could equally be an enemy, a rival, a bitter ex, or whatever else. And the NPC could be there for a reason directly connected to the PC or indeed for an entirely unrelated reason - which could be as simple as "I had an invitation".)

The reason for wanting this anchor NPC on the scene is that something bad (TM) is going to happen at the party which will trigger the first adventure in the campaign, and while that event will proper the PCs to direct action, it will be more interesting if they care for some NPCs so that the story isn't just "how to we get out of this" and turns into "how do we rescue (or not) these other guys as well?"

It will, of course, be my intent to use some or all of these anchor NPCs later in the campaign, in various capacities - some will be allies, some may be enemies. Of course, some may not survive the first adventure!

My goals for this first adventure, then, are two-fold:

1. Meld the individual PCs into a somewhat-coherent group. This shouldn't be a big issue, since the players will hopefully do that well enough.
2. Prepare the anchor NPCs for world-building use.

And it's worth noting that one of my players has suggested an angle that is very interesting, and something I most likely would never have considered on my own. Which is extremely cool, and one of the great advantages of the tabletop RPG form. Yeah, I'm looking forward to this campaign.