And hopefully this has not been posted before.
I have been using Glint's Challenge as a practice for my UW Terra build. At first I was doing NM with my heroes on one side and I took the other side. Then I realized I could actually do both sides as long as I stand in the middle and let my dwarven friends die... At last I found out with the addition of Armor of Earth I could actually go HM on this thing. A typical run for me would last about 9 minutes (as I only solo the first wave) and usually I would get 1-4 golds, 2-8 D cores, 0-1 lockpicks, dyes, tomes and of course, purples and blues and chalks -- from a total of 60+ lvl 24 destroyers.
I have not learned how to show the interactive skill bar yet, so allow me to express them in words

I have 16 earth, 9 fire, 5 energy, 4 air and 9 inspiration (edited) for my attributes
I use a Drok's earth staff which has +20% enchant and half skill recharge, etc. Caster modded swords and shields would work too but without con sets the 20% chance half skill recharge on a staff helps a lot.
My build is:
Glyph of Swiftness
Obsidian Flesh
Stoneflesh Aura
Sliver Armor
Armor of Earth (a must in HM)
Lava Font
Mantra of Earth
Stone Striker
(edited) To view this interactively please refer to this thread's first reply by Koricen

By the way, this build does not need any hero monks, or any hero for that matter.
The overall walkthrough is simple. You take the challenge from Oakencask, run and position yourself in between the two dwarfs in the center -- your back is facing the little cliff that separates you and the baby dragon. Then you wait. Wait till the destroyers kill the first 2 dwarf warriors (2 on each side) and just about to kill the first dwarf rangers (2 on each side too). Now you cast GoS, Obby Flesh, Stoneflesh, Armor of Earth, Mantra and Stone Striker in sequence. After you cast all of these the second dwarf ranger should be killed by now and destroyers would start wanding you and feed you with energy

Aggroing is a bit tricky here. You want to walk a little away from your original position -- away from the direction of baby dragon. If you stay too close to the cliff some destroyers on the left side would break off from the main left ball and start attacking the dragon, and the run would be over soon. Keep all your enchants on -- especially obby flesh, stoneflesh and armor of earth. In HM without cons timing is critical. You want to make sure you leave no downtime at all for all these 3 enchants. Focus on enchanting till about 3:30 minutes in time -- this is when all the destroyers arrive. Count them there would be over 30 on each side.
Now, walk towards right side and use sliver armor to kill. 15-28 dmg times 60 per second is a huge spike. You should be able to annihilate the entire right group within the second recast of sliver -- swiftness on sliver is a must if you want to be fast. Lava Font is optional in the right group because of the huge triggering of sliver.
Then, you walk towards the left group. By now the left group becomes a nice, compact ball. Trigger sliver again and begin the slaughter. Lava Font would be a nice addition. Within 3 minutes you should be able to cut their number down to 3-4. At that point in time, which is around 8:30-9:00 minutes I would call it and start another run -- as sliver becomes much less effective with this few foes.
Taking into account the time to merch, I can do about 5 runs in every hour and get about 20 D cores plus around 6-10 gold weapons and some lockpicks. It certainly is not the most profitable farming run in GW but it is decent, and definitely a nice way to farm D cores.
Hope you guys can all stand this dryness without intensive imaging

Good Luck and Good Game!