Spend enough time in Diablo IV's endgame and you'll notice the real wall isn't Sparks. It's runes, and that's what slows Mythic crafting to a crawl. A lot of players keep bouncing between Helltides, bosses, and random dungeons, then wonder why progress feels awful. It's not that the drops are impossible. It's that the route is bad. If you're chasing efficiency, or even browsing stuff like diablo 4 season 12 uniques for sale while planning your build, you'll get more value by locking into one repeatable farming loop and sticking with it.

Why Kurast Undercity beats everything else
Right now, Kurast Undercity is the place to be, but only if you're using Tributes of Harmony. That part matters. Without the right Tribute, the run just doesn't pay out well enough. With it, the results are hard to argue with. Over a decent stretch of runs, you can expect legendary runes at a rate that leaves most other activities behind. And the best bit is the pace. A strong build can finish an Undercity run in under two minutes, sometimes faster if the layout is kind. That's why people who still farm runes through world content usually feel stuck. They're putting in time, sure, but not in the one activity that actually turns that time into runes.

Run it fast, not clean
If you can handle Torment 4, stay there. Torment 3 might feel smoother, but the drop difference is real enough that it's not worth settling. If T4 still feels rough, that's your next goal before anything else. Once you're in, don't play like you're clearing a dungeon for the first time. You're not there to admire the map. Hit the pylons, push the reward bar to level four, and go straight to the boss. That's the loop. A lot of players lose time chasing treasure goblins or drifting into side packs, and it adds up fast. One run doesn't seem like much, but over an hour it's the difference between a good session and a waste of one.

Keeping the Tribute supply alive
The awkward part is staying stocked on Tributes of Harmony, which is why the Tree of Whispers still matters. You don't need to live there, but you do need to feed the machine. A smart way to do it is to pile up a batch of caches first, then open them together. It breaks up the grind and usually gives you enough fuel for a proper farming stretch instead of a few runs and a stop. After that, don't forget the Jeweler. Three lower runes can be combined into one higher roll, and while it's obviously not guaranteed, it's useful when you're short on one piece of a recipe. It's not glamorous. Still works.

Don't throw away the rune you actually need
When you're finally ready to craft, slow down for a second and read the recipe properly. People get impatient, click too fast, and burn a rune they meant to save. That mistake hurts more than a dry farming streak. The cleanest approach is simple: gather Whispers, stock Tributes, spam fast Undercity runs on T4, then use the Jeweler to patch missing pieces before you commit. Do that and Mythic crafting feels way less random, way less annoying. It's a far better path than roaming around for hours and hoping luck shows up, especially if you're already mapping out your gear alongside https://www.u4gm.com/diablo-4/items