Motes. It's how you upgrade Sky stuff. Getting an item to +5 doesn't require that many, really, so it's a waste of time to do epic quests more than once.
The best mote farm is the real end game goal. That's the big question. It might be D4 sky bosses with a top tier build or AoEing crap in D4 hate/fear or destroying lower level dungeons on twinked level 10s.
I got several high tier motes in my single D4 Sky run:
[Fri Jul 17 03:00:37 2026] --You have looted a Mote of Major Potential from a blade storm's corpse.--
[Fri Jul 17 03:15:15 2026] --You have looted a Mote of Superior Potential from Noble Dojorn's corpse.--
[Fri Jul 17 03:41:58 2026] --You have looted a Mote of Major Potential from Bzzzt's corpse.--
[Fri Jul 17 03:49:21 2026] --You have looted a Mote of Grand Potential from Bazzt Zzzt's corpse.--
The problem is the 'motes only work in certain tiers' thing (which seems legacy after the spell upgrade stuff) makes straight mote farming suboptimal by a good margin. The three things that define the problem are a) the xp gain from motes does not increase geometrically b) motes of a certain tier can only upgrade an item to that tier c) item -> item merge does not have any restriction.
This means cramming lower level motes into a donor item and then merging the donor item will have increasingly large benefits the higher the tier disparity between the motes and the item you're upgrading.
For reference, motes increase from t0 to t9 as 1, 1, 2, 4, 5, 6, 7, 8 ,9, 10. You can 'upgrade' motes at the construct in town at a 2:1 ratio, but the next tier mote is normally only +1 xp value while costing 2x the previous tier. From t1-t3 there is no loss (1, 1, 2, 4) but after that, you are trading 2x4 for 1x5, 2x5 for 1x6, etc. This compounds so as you merge motes up, you are discarding more and more xp just to be able to get the mote to be merged into the item. Spells do not have this restriction so your tiers of motes are just different 'bang for you buck' drops (they can drop 1x10xp mote instead of having to drop 10x1 xp motes). This being the case, you can 'smuggle' the motes losslessly into a higher tier merge via a donor item. A donor item contributes the amount of xp it took to get it to its current tier.
Motes really should just be like c/s/g/p where they are denominations of the base MOTE == 1 xp. This way you can convert them as needed or just grab a stack of 32 or whatever if you need 32 xp for an upgrade. The tiering system means you lose approx 1.5-1.7x per tier difference between the motes you have and the item you want to upgrade. This leads to esoteric knowledge and noob traps, it also leads to potentially maladaptive behavior like farming up multiple donor epics / quest rewards so you can ease the later transition to +10 via more efficient mote economy.
