Looking for ideas for a Vecna/Planescape campaign after a heavily modified Icewind Dale [SPOILER]
I'm currently running a heavily modified Rime of the Frostmaiden. I'm keeping most of the locations and the sandbox structure, but I'm slowly tying the campaign into a bigger mystery involving Netheril, Ythryn, chardalyn, the Spellweavers and the black obelisks that appear throughout 5e.
The players currently think Auril is behind the eternal winter and that she's trying to protect some ancient source of power beneath the glacier. That's meant to be a false conclusion. Eventually they'll discover that something much older is going on, leading to Vecna.
My plan is for the first campaign to end in Ythryn, with the PCs eventually confronting Vecna. They refuse to serve him, so Vecna kills the entire party.
Then the players wake up in the Mortuary in Sigil.
They slowly realise that they're actually playing their old characters, resurrected after Vecna killed them. Sigil becomes the base for the second campaign.
In my setting, the Lady of Pain is the last surviving Spellweaver. Vecna exterminated the Spellweavers thousands of years ago, and she survived. She's not going to be their mentor or explain everything to them; she simply has her own reasons for wanting Vecna stopped.
The big thing I want to build the second campaign around is the black obelisks. I love the idea that they're part of some ancient Spellweaver network capable of manipulating reality, and that Vecna has spent thousands of years learning how to use them.
What I really like is the idea that Vecna can't simply enter Sigil, so instead of finding a way into the city, he uses the obelisks to somehow bring Sigil to him — essentially manipulating reality until the distance between Sigil and himself stops meaning what it normally means. The ultimate goal would be to use this to reset/remake reality.
This is where I'm stuck.
I don't want the campaign to become "find obelisk A, fight something, find obelisk B, repeat". I'd rather the players gradually figure out what the obelisks actually do and then decide for themselves how to interfere with Vecna's plan.
Ideally, the things they accomplish during the campaign would affect the final fight. If they completely fail to understand what's happening, Vecna reaches the final confrontation at full power. If they figure out the obelisks and manage to sabotage or manipulate the network, the final fight becomes significantly easier.
I don't really care about sticking to official lore. I'm happy to steal from old editions, Planescape, other D&D adventures, video games, movies, books, whatever.
Has anyone done something similar, or have any ideas for how Vecna could use the obelisks to "bring Sigil to him", and how the players could fight back without turning the campaign into a series of fetch quests?
I'm mostly looking for cool ideas to steal. 😄