Hey, question about 3rd gen DK’s! Do you know if Eternal Hunger is directly tied to the runeblade?
It’s honestly unclear, but my inclination has always been yes.
(Mix of canon and headcanon ahead!)
This is because in the intro quests, it isn’t until after you make your first runeblade that Razuvius informs you that you have “the mark of war etched upon you” and “the endless hunger will soon take hold of you”.
While not maliciously sentient like a lot of infamous named blades, a 3rd gen DK’s runeblade is still vampiric. This means that it feeds on the essence of its victims as a means to empower its runes, which are constantly being drained to strengthen the wielder and thus constantly in need of charging. The endless hunger is a manifestation of its demand.
It can be satisfied by inflicting pain, but only in the way that itching a rash can make it feel better momentarily. It doesn’t cure it-- that requires killing, and it will still come back. Disposing of the blade is a death sentence, because its power is what maintains their physical condition and they will wither away without one. If they need to replace the one they have, it needs to be immediately.
(Some people, like myself, prefer to RP their DK being bound by their soul to a specific, irreplaceable blade. This is not necessary though; it’s made very clear that blades can be replaced.)
It’s possible that the hunger is something just “programmed” into them the moment they’re risen, though, as a means to keep them under control. If a mind is occupied by a constant stream of murderous intent, it’s not likely to question the morality of a situation.
If this were the case, however, that would mean new DKs (those risen at the Broken Shore) would not have it, as the Ebon Blade, while guilty of some repugnant things, isn’t the Scourge. Thus, I relate it more to the runeblade, or perhaps a little of both-- meaning that the new knights don’t experience it to the same degree as those borne of the Scourge.
There is also a theory that the shades that torment death knights are somehow connected to the hunger. Arthas implies that in his service they were kept at bay but those who left are no longer protected from them. Perhaps the inscription of runes draws them near to nag at the knights, but outside of that quest they are never addressed and I personally don’t think they’re related.