In the "Age of Worms," write up for Diamond Lake, there's an end piece that lists off ideas for each character class and race for tying the PCs into the adventure path.
I figured that since this board was such a font of ideas, mayhap I could share a few of the tie-ins my players knowingly came up with (and some I unknowingly added to them), and share ideas of the sort. We're only at the start of the Lava Tubes in "Flood Season," so ideas are still easily added at this point...
A few off the cuff from my group:
Those poor highpriests! - a PC is the child of one or both of the previous shrine high-priests of Pelor, now under the somewhat dubious care of Kristof (who isn't the most effective guardian). In my campaign, this is the Fighter/Cleric (and eventually to be Radiant Servant of Pelor). The "tragic accident" death of the priests is never revealed, but again, in my campaign, I've had it that Ike arranged a landslide when the pair were coming up one of the roads into Cauldron. So sad, really. He'll eventually slip during the players' invasion of the Temple of Wee Jas and say something like, "Oh, the child is here. And no convienient tonnage of rock to bury you with. Your parents really were more accomodating!"
'The Risen,' were a great adventuring band, until they sort of vanished - Again, going for parentage or family ties, someone close to the PC is now a statue in Vhalantru's house. In my campaign, the Rogue/Diviner is the daughter of a pair of adventurers who, with their two companions, are in Vhalantru's house. The Rogue/Diviner was left in the care of Rivek Mol (of the Tipped Tankard) who, realizing that the parents weren't coming back from the "difficult task," eventually placed her with Gretchyn at the Lantern Street Orphanage. He kept her inheritance - feeling he'd explain who she was and whatnot and give it to her when she was older (and then a Last Laugh guildmember stole it and the Rogue/Diviner had to recover it on her own). Added benefit: when the party gets to Vhalantru's house, you can insta-followers with the character's own parents...
As we talked about in our other thread, I am one for subbing minor characters with the PCs and then working them in.
Rogue
Patch, the half-orc dup of the Last Laugh who had been assigned to watch Terrem at the Lantern Street Orphanage is easily replaced with the PC. The PC then gets some modicum of training from the last laugh and has a reason to search for the children (a notoriously tough thing to do for some rogues who like to be loners).
Cleric
Replace Ruphus Laro with the party cleric and you have a built in introduction. It may mean changing the church from St. Cuthbert to whatever is appropriate, but that isn't a large deal in most cases.
Wizard
Apprenticed to Maavu? Give them perspective of how the merchants are feeling. Taxes, etc.
Fighter
This character could be a member of the watch finishing his stint. He would have been on the group assigned to track down the missing children and would start play with the list of abductees and the info you get from speaking with the watch.
Sean Mahoney
Excuse me, have you seen my cousin? - One of the PCs is related to one of the kidnap victims in "Life's Bazaar." Even better if this is someone that is already sold and somewhere else - you can plot them in at a further junction (ie: one of he halflings could have been sold to Thirifane, and is now an animal whose simulacrum is acting as a servant).
Cleric - Wee Jas - There are rumours about the Cathedral in Cauldron, and you've been asked by the church in Sasserine to go to Cauldron, keep a low profile, and see if you can determine anything off about the sister church there. It might be a bit of a balancing act to keep the Cleric far enough away from the Cathedral until the right time, but (s)he's bound to be interested in anything that goes a bit strange in Cauldron.
Monk - A probationary member of the "Order of the Silver Dream," you've been trained on how to hunt bad things for most of your life. Now you've begun your walkabout, where you are to pick a place, defend it from the undead and other horrors you've been trained to defeat, and upon defeating something terrible, return to the Order and receive your status as a full member. Afterwards, you're assigned to Cauldron.
The Necromantic Con-Job - For a good aligned person with a slightly larcenous streak, we used this in my campaign as a bridge to get some characters a bit more XP, but it could also be back-story. Someone magically trained became aware of a deal going on in Redgorge. Someone in or around Cauldron paid to have a fetish made and delivered to Cauldron. The fetish was obviously part of a lich-creation-ritual, and the PC is/was hired to switch the fetish with one that looks the same, but is - magically speaking - sabotaged. Once they give the real fetish to the arcane figure in their life, he grows puzzled, saying, "That's odd... it's attuned to gnollish blood. I don't think I've heard of a gnoll lich before... Either way, if the vile creature tries to use the fetish you left behind, it will explode." When the PC later meets Tarkilar, they can feel a bit of pride that they're not facing a Lich.
I had everyone get thrown in jail and harassed by Sheriff Cubbin. Most of them are there on illegal charges, having been betrayed by various benefactors, and need some money fast. They meet each other in the holding cell after their initial intimidation sessions. In every case, a payoff will cure all ills, and he plans on releasing each character later on that day, after he reports their behavior to the various wronged parties and cover-up partners.
The new deputy, a half-orc, is in charge of the holding cell, and he has the Whispering Cairn location map. However, he can't read it and needs someone who can. He figures that the PCs would be desperate enough to go adventuring, and asks them if they'd like to do a job together, Usual Suspects style.
It was fun, and it gets everyone pissed about Diamond Lake and its corruption.
Great thread!
Druid or ranger
A member of the Striders, tasked by Meerthan to form an adventure company and gain the trust of Vhalantru. In this case Vhalantru is positioned as a patron to adventurers. The striders know Vhalantru is corrupt, but have no idea as to his real nature or his involvement with the cagewrights. The PC must find out to what extent Vhalantru is involved with this group.
Any Character
The character in the proces of being kidnapped, but the kidnapping is interrupted by either another PC, the last laugh or a member of the city watch (or all three). The character saw/heard a fragment of his kidnappers, but not enough to identify anyone.
Cleric - Pelor - Kristof is over his head, but there's no one extra to send to Cauldron right now, so the PC is it. Investigating the "tragic" deaths of the former leaders of the Shrine is one thing, but acting as Kristof's 'right hand' is another - especially when the man seems so unfocused and overwhelmed. He tends to give really vague instructions like, "See about this kidnapping business!" and "Find out if anything is needed for the Flood Festival!"
Rogue - Being a junior member of the Last Laugh Guild isn't all it's cracked up to be - especially since they seem to have decided you should go on more and more dangerous missions of late (it might be because you didn't kill that person they asked you to). It might be time to break from the guild - but who is going to keep you alive if you do?
or, alternately...
Rogue - Those damned Last Laugh people ran your small guild into the ground, killed nearly everyone, and left you to die. But you didn't. And now they're going to pay, however you can deal it to them. If you see a Last Laugh guildmember do anything, you're getting involved on the other side...