Well, let's get back to Karlach, then. Time to remind people, old and new, how trivial Karlach's problem is in the grand scheme of things when it comes to DnD.
Below are some examples from in-game, that would offer solutions, but are never explored.
Spoilers, of course:
- Enriched infernal Iron. You can loot that, and it does nothing. Convenient. - House of Hope & Raphael. I'm sure a demon/devil/whatever, who is a direct competitor to ZARIEL, might be interested in a transaction with SOUL COINS. You know, the infernal currency we find throughout the game? - Divine intervention scroll? No? Anyone? - Even Mizora might help, just to be spiteful. Or wanting a deal. Them winged ones sure like deals. - During the game you can help multiple gods. Why wouldn't they want to repay that? Would be another Tuesday for them. - You have Withers at your camp. Why can't he true res Karlach for a fee? "But it's a game mechanic" you say? It's still a resurrection. Have permadeath if you think resurrection has no place in DnD. - Speaking of True Res, Gale has a SCROLL of it later in the game. Perhaps he'd be willing to part with it. Or maybe his cheese buddy Deus Ex Elminster has solutions? - Wish spell is in the game, Vlaakith uses it on you. After all we did for the world and gods, we'd sure love one wish spell. Is Vlaakith the only god who can wish? - But, the most obvious are the Gondians. You know, the INFERNAL MECHANICS you save/meet, who have PERFECTED and UPGRADED the same engine Karlach has. Why is this completely brushed off? "But open heart surgery!" Oh come on. There are talking heads. You can sleep with a bear. Magic, gas forms, resurrections, telekineses, submarines and gods are around, and you draw a line in heart surgery? - Hell, even Gortash might trade them schematics/newer engines for his life. Would fit perfectly with his character.
But we did all we could.
Karlach's fiery, poignant and bittersweet endings would work if the game was set in another setting. Set in the modern, real world? Most definitely. Sci-fi? Most probably. Low fantasy? So and so, but could work. High fantasy DnD? Not at all.