I think there is a small chance of luck involve, because when I pulled the guards, one of them actually respawned, so I end up fighting 3 guards before boss came down from the dragon, the orc isn't hard, I finish him off fast before dragon landed, than I ran forward towards dragon as it came towards me, I use Rightouse Defense to aggro it because it is going for my healer, and for some reason, I was facing my group with dragon facing me, this made a lot easier as it's flame AoE can only damage me. I throw out everything i have, summon 2 water elements, and watch my tank's health very carefully so it doesn't get below 35%.