HaroldTheHobbit
Hero
It's a General D&D thread, and in older D&D one component is - at least how I understand it and GM it - than not all encounters are meant to be able to beat for the PCs, at the current level, without the artifact weapon etc etc.Fine. Have your characters die. Have fun.
The point is that there is no "trigger" - it isn't/shouldn't be a specific act on the GM's part to kill the character. The GM provides challenges. You beat them or you don't.
In those cases the GM explicitly create TPK encounters, ie encounters that kill players if they engage in it at the current power level and point in time. That is definitely a specific act of the GM to kill the players, even if one semantically construct it as GM-neutral encounter within the framing of a specific game. A TPK encounter in those circumstances is not made out of malice, but out of an implied playstyle that lots of players still seem to enjoy.