Jultharin is the second last boss in Charmer’s Caldera and is entirely a gear check. If you can pass Jultharin you have the gear to do all of the T2 content easily.
Abilities
Deranging Tempest: Summons a line of orbs that will instantly kill an opponent
Shocking Blast: Single target air damage on target of boss.
Daze: Dazes a target causing them to confusingly walk around.
Strategy
So as far as a setup goes you want to be like this:

The goal here is to start off as far away as possible and just grind the boss down.
The orbs you see in the picture (red line) will slowly close in on you. This gives a direct timer for how long you have to kill this boss.
You have two options as far as makeup goes. The first is you can choose to run your healer as a DPS and have your support heal everyone. If your support is geared enough he should be able to keep everyone up while still DPSing. My rogue solo heals a number of bosses so as long as people are being smart it’s easy.
The other option is to have your support transform into a full on DPS (the more common option). In the kill video our makeup is one healer and one support. It just so happens that I forgot to transform into a DPS, however because it was a guild run it was not necessary.
A big tip is to not run off the edge. Sounds dumb but when you are dazed make sure to mouse turn and not keyboard turn around. Sometimes if you keyboard turn around you’ll push yourself off the edge.