Another of my "Does this exist" Threads! One thing that I have noticed being a common occurrence in Cultivation Novels is that, despite how much time passes in them, nobody really dies of old age in them, even if their cultivation levels lifespan mean that they should have died of old age ten to twenty Closed Door Cultivation Sessions ago. Okay, sure, there's the occasional person, probably an old mentor relative, who's at the end of their life when the story begins, and dies before the MC is probably in Foundation Building Stage, but that isn't what I'm looking for here. No, what I am looking for is for a MC who's grown at least one or two stages above his friends, and thus has a significantly longer lifespan, coming out of 1000 years of closed door training only to find out that at least one of his friends, or enemies, hadn't managed to improve their rank, and died of old age while he was training. More likely, however, he comes out of closed door training to get to speak to his friend one last time before they die of old age, sitting by their bedside as they die. If you could please inform me of a Cultivation story where the Time is treated properly like this, I would appreciate it.
Desolate Era has a little of that (in the various "returning home to tie up loose ends after becoming OP" mini-arcs), but only for side-characters who have already been gone from the story for a long time, people you probably forgot about by then.
Warlock of the Magus World, you'll see it a lot, there are many "important" characters that you'll see dying because of old age. From my little knowledge of Chinese web novels (多い) WMW is one of the best when it comes to that.