#squinky

I figured out how to run this with a fresh party, since OP Squinky is tied to a specific party history, and losing the "you created this villain" would take a lot of the shine off:

The first quest is to help a small child find their lost pet. The poor thing's wandered into a dungeon! have them find the animal recently killed, and make sure the party has access to a spell that can revive it - put a scroll or smth in the dungeon if they don't have it in their spell lists. A good way to subtly encourage them to have it is to let them start at a level where they can cast it and then emphasize that the campaign has a high lethality rate. Emphasize the joy in the child's eyes when they return the revived pet.

Go off and do a different adventure. Meanwhile, that kid has taken up their own adventuring career, and they're studying necromancy so they can help other people the way you helped Squinky! (if the players didn't say he was revived then the kid can have found out through some other way - maybe even a speak with animals spell!)

Have them run into this greenhorn and their animal companion. Make sure the kid is helpful and not annoying or the party won't like them. It's important that the party likes them, and the best way to make sure players bond with an NPC is to have that NPC be useful, or have them always arrive with Fun Times.

Each time they meet Squinky's owner, Squinky's looking a bit more beat up. But Squinky's owner doesn't seem like they're being *unkind* to squinky; they give squinky everything he needs, and clearly they love this creature a lot.

Then the party stops seeing squinky's owner around. If the party doesn't notice or thinks you just forgot these characters, have NPCs in towns remark on the apparent disappearance.

Then they start hearing rumours of problems with necromantic magic not working right, or maybe they get a call for aid from a dwarven necropolis whose ancestor-shrines have been defaced.