This fight was not easy as it looks. It took us awhile to get him down. The next bosses are very hard. We each played 5 characters during this kill.
We had 3 of my dps running to the crystals. My tank and healer were following Merc. We used the spires north and south so we didn't aggro the mobs on the side. Merc called out taunts as I was running around. It should be much easier next week.