WILLITH
Class Mastery
Lead from the Front - provides group wide major berkserk and major protection for 1 sec per 15 ult spent. Paired with Standard of Might which needs to be placed in group for everyone to benefit from so swapping this out for Magma Shell or War Horn in bosses where this isn't possible might be better.
Resolute Defense - increases the amount of damage you block the longer you block. Also has a chance to restore stamina
Booming Voice can also be used instead of Resolute Defense if you find you are lacking sustain instead.
Skills
There are a few complexities to the DK tank regarding skills. A lot of their skills are close range and single target which isn't ideal for the ice dragon or add pulls.
For add pulls, Elemental Susceptibility is swapped out for Razor Caltrops and Leashing Soul put on the front bar.
Heart of Flame gives you a ton of sustain by giving you a portion of your missing resources back plus a bit of health. A very solid bit of sustain for DKs.
Fossilise is another one, as the range is only 7 meters so using this on a boss where you have to maintain distance like Lokkestiiz in Sunspire (Ice dragon) isn't feasible. Magma Fist can be used instead which provides a unique ~4% dmg taken debuff at the cost of being expensive in stamina.
Hearth and Home gives you nice major protection and minor heroism and healing while in its area but can be replaced by Blood of the Green Dragon if you feel that you need a burst heal instead.
Igneous Weapons is a support skill for classes where major brutality/sorcery isn't easily gained, also lasts a minute so should only need to cast a few times a boss.
Igneous Shield on the close range setup and Blood of the Green Dragon on the long range setup are flex skills that can be changed with whatever you wanted, but just a demonstration of useful skills for survivability.
Dragonknights don't have a class source of minor resolve so I've put in Ulfsilds Contingency with dmg shield and gladiators tenacity to deal with that. It's not ideal but it will give you the mages guild passives which are good to have.
Sets
Throughout the trial, Yolnahkriins will be worn on the body so everyone is getting minor courage.
For add pulls, use Vateshran on the front bar and Turning Tide on the back for conal major vulnerability.
In bosses, switch out turning tide for Stonehulk Domination which will proc major vulnerability on taunt. A single taunt will be kept on one bar so that this is kept up. Vateshran can be replaced with 1pc Trainee and 1pc Druids Braid if it feels necessary. Same with the double barring of Stonehulk on the Long/Close Range setups.
For set traits, I've put the big armour pieces in reinforced but these can be changed to sturdy or divines at your discretion depending on whether you can make the armour cap without it.
Infused traits on the jewellery are recommended as the main tank is usually on their own so self sufficiency is key.