Vanquishing was quite taxing job for me before and I struggled a lot.
I remember vanquishing Old Ascalon and it took me almost 2 hours by myself. I recently made a build for my monks and that uses Unyielding Aura on both of them with the exact same skills. All healing skills heal 50% more and are divine favor skills that also benefit from the extra healing divine favor offers. So all the spells heals for double the amount and are party wide.
Then I added some Mesmer skills for energy management and interrupt. A rez isn't worth bringing as UA acts as an instant rez when someone dies (if someone dies).
My buddy takes some Discord and MM heroes and I equip my scythe on my warrior with Save Yourselves! and some strength skills as well as Aura of Holy Might. Also I add Warriors Endurance for energy management and just let loose an average of 150 damage per attack x3 as the scythe attacks 3 enemies if positioned right.
Now HM has become NM. Actually HM is laughable at best with this combo.
Here is the template code for the build I'm using:
W/D Endurance Scythe: OQoiExpMZXIDKU0c9f1pFDyXBA
* Can swap Flail with Pain Inverter, Asuran Scan or Light of Deldrimor for extra AoE damage.
* Critical attacks against bosses (lvl 28) can yield around 210+ damage.
* Undead suffer completely at anything from 250 - 522 damage per shot.
Monk 1: OwUVMw26k3AXihoBsL6iAjIDoHACEA Uses Spotless Mind for Hex Removal.
Monk 2: OwUVMw26k3AXihoBsL6iAjIDoHICEA Uses Spotless Soul for Condition Removal.
For Discord heroes you can check
PvX Wiki for the complete set of builds.