One of the PC's backstories says her family is poor money-wise because they're indebted to a noble. I'm running w/it and saying:
The PC's grandmother was a witch. She wooed the wicked lord into infidelity, promising him wealth and power. She got a daughter out of the deal while the lord got control over an undead horde. He didn't realize though that this control came at a price; the undead were greedy sob's in life and demanded all the new-found wealth he'd acqired.
The lord's line and the witches continue on to this day. The witch's line descends to the PC while the lord's line ends with the noble house she's indebted to.
The PC's family then lives under the constant threat of being exposed and prosecuted for their infamous ancestor while the noble house extorts money to maintain the undead horde they no longer want or need, kind of like having a crazy aunt locked in the cellar. Now that their forturnes are waning they are throwing a hail mary and intend to sacrifice the PC in appeasment.
So... I have the original seduced lord (now transformed; I'm thinking an orgre magi), the old witch, the undead horde, and a few minions. Do I have too much going on?
I would say you are fine, but I would have the noble dead and risen as a skeletal champion or a dreadknight (or ghoul) indebited to the unappeased hoard. That way the noble family can bring him and the horde offerings of flesh to keep up the bargin. The ultimate offering being his out-of-wed-lock daughter, this would release him from his bond to the horde.
My 2cp
Too much? Not at all!
Also, The Shogun's idea is great.
Nope, this is great - as long as you're okay with bending to the PC's decisions! This is a fantastic setup to give the character some personal motivation to act, and the PC may even do something you wouldn't expect. If you're cool with that, go for it! Even though it's good to keep things simple, at the same time, your campaign, story, and villains can never be too rich (in content, numbers, etc). It's not all going to fall on the PC's head at once (or it shouldn't, anyway). If nothing else, it just gives the PC that much more to look forward to. Your players can never have too much motivation / too many things to look forward to. Good stuff.
Just weave a few of the other PCs into the brew. The Noble family sounds like a crew that could have more than one such plot running. Perhaps one or more of the undead have further connections back into the families' members. A raised retainer or defeated foe would bring another level of treachery possibilities.
I should clarify: I began with another PC having lost his parents; turns out the fey killed them when they got too close to substance that can be used against the fair folk. So starting off on that plot line I have the PCs long-lost sister back from the fey realm, hunting down more of the substance, and using a bunch of goblins and bugbears as her muscle.
I think this is why I thought it might be too much. I've got one main villain in the sister and goblins, and another in the nebulous force of the "fey of the woods" who are currently being hunted a la "wingclipper" from the dungeon adventure by the PC's sister.
So now I'm 2 sessions into the game, put a request out to clarify something with the other PC, and she tells me "oh yeah, by the way; my family's in debt to a lord in the town. Can we work that into the story?" so then I came up with the OP.
Do you think I should keep the plotlines separate and risk too many villains, or tie them together somehow?
The great thing about too many villains is that the players can start defeating them 1 by 1
You are golden, keep them seperate.