After a few nights of endgame grinding, most players hit the same wall: not Sparks, but runes. That's the part that slows everything down. You can have the boss mats, you can have the plan, you can even check diablo 4 s12 items for sale if you're sorting out the rest of your setup, but Mythic crafting still stalls if the rune stash isn't there. And that's why random farming feels so bad right now. You're not really making progress, at least not steady progress. The better move is to run a loop that feeds the exact resource you're missing instead of hoping the game just hands it over.



Why Kurast Undercity is the best route
If your goal is rune income, Kurast Undercity is where your time should go. Not sometimes. Pretty much every session. The important part, though, is using Tributes of Harmony. Without those, the place drops off hard and the efficiency just isn't there. With them, the returns are way more consistent. A lot of players have noticed the same pattern: roughly eight legendary runes from ten completed runs, give or take. Since strong builds can clear it in under two minutes, the runes-per-hour is hard to beat. World bosses and normal dungeon clears can still drop useful stuff, sure, but if runes are the target, they're just slower. Simple as that.



Run it fast, not clean
This is one of those spots where playing on Torment 4 really matters. Torment 3 feels easier, and yeah, it's more relaxed, but the drop rate difference is noticeable enough that you'll feel it over a longer grind. If T4 still feels rough, that's the job first: get your build over the line. Once you're there, stop treating Undercity like a full clear activity. It isn't. You want the pylons, you want the reward bar capped at rank four, and then you want the boss dead. That's it. A lot of people waste time chasing side rooms or goblins because it feels wrong to let them go. Don't. Goblins are bait in this loop. They pull you off pace, and pace is the whole point.



Keeping the tribute supply alive
Of course, none of this works if you run out of Tributes. That's where the Tree of Whispers comes back into the picture. It's not the exciting part of the process, but it keeps the machine running. A good habit is to save up a stack of caches instead of opening them the second you get one. Crack open ten or twelve in one go, then sort what you got and head back into Undercity for a proper farming stretch. It feels smoother that way. Less stop-start, less checking bags every few minutes. And when your stash starts filling with lower-tier runes, the Jeweler becomes useful again. Three-for-one upgrades aren't reliable, but they do help when one missing rune is holding the whole craft hostage.



Don't throw away the rune you still need
The annoying part comes right at the end, when you're finally ready to craft and one careless click can wreck the whole thing. People do this more than they admit. They convert or spend a rune they meant to keep, then realise too late it was part of the recipe for the item they actually wanted. So slow down there. Check the ingredients twice. Maybe three times if you've been farming for hours. The cleanest path is still the same: Whispers for Tributes, fast T4 Undercity runs for runes, smart upgrades at the Jeweler, and only then the craft. Follow that loop and you'll finish your gear much faster than the players wandering Helltides and hoping luck sorts it out, which is why a lot of veterans pair that grind with planning around https://www.u4gm.com/diablo-4/items