Better option TPK them then bring them back only for the villain to say they’re not worth the effort and shunt them off to god knows where so they can get stronger and do it all over again. Or kidnap the NPC

6

If you’re my DM, no you should give us 2 level ups and a cookie If you’re not my DM, TPK them, but then have them all wake up in hell and give them the chance to fight their way out to get revenge. If they manage to pull it off, let them know that time passed differently in there than the material plane and they’d vanished for months. Let them slowly find out how their families & friends thought they were gone. The NPC got spared but allied with the BBEG to stay alive

1