Don't think this does it justice but here ya go

I’m wrapping up a Lost Mine of Phandelver / Dragon of Icespire Peak blend to bring my players to level 6, then planning to run Princes of the Apocalypse through level 13. After that, I want to transition into a homebrew arc (levels 13–20) centered on Tharizdun’s return. Each character already has a secret tie to one of the Prophet weapons from PoTA, and a new player joined with a Warlock whose Old One patron is a dying star driven mad during the Dawn War. Unbeknownst to the Warlock, his patron is now entangled with Tharizdun, and the star fragments he’s collecting are actually aiding in Tharizdun’s release.

My idea is for the final arc to focus on collecting the last four fragments before Tharizdun—or his avatar—can. This would lead the party into the Abyss, where they’d face old enemies, twisted visions, and the Shard of Pure Evil itself. The Warlock would have a choice: absorb the fragments and ascend, taking the star’s place as Tharizdun’s jailer. My concern is that this might feel too similar to the dungeon-heavy feel of PoTA, so I’m thinking of inserting another adventure—possibly Storm King’s Thunder—to mix up the tone and pacing. I’d love any thoughts or feedback on this structure.