Figure I'll give a heads up on the best way I found to deal with this quest.

Once on the dragon, go to the floating platform, land or hover, either is fine, this will stop you from falling all the way back to the bottom, or in some cases, falling to your death when the dragons attack you!

Next, make sure to get on of the ones that circles the Nexus, they are less likely to pull any other dragons. No matter how good you are at this, you cannot take two at once!

When attacking them, use Flame Spike, as fast as you can, and once you've hit them 5 times, use Engulf in flames. then repeat. Can only repeat twice, cause the energy will be too low to pull off the Engulf attack. As the battle wears on, the energy can charge back up to do a third, but usually not, or best not too because of Arcane surge. Watch this attack. If you see it charging, wait till it is almost charged right before it attacks you. Hit Flame Shield. No matter how many combo points you have up, at least 1 should let you survive the attack. More though will keep it up little after the attack, and give you a bit more health to keep fighting.

Once dead, click on yourself, and Revivify 5 times then life burst. Doing this twice, should get you back in the battle. Just make sure to wait till the energy is back up, or you'll be off to a bad start based on my attack pattern.

Another trick, that helps some times, is fly close to the center platform, and pull a dragon that is by it self, and back up as you attack. Once it hits you when it's in melee range, it doesn't usually fallow you unless you get out of it's fire range. this will cut down on the slashing it dose. Just make sure not to fly past the platform I said to work from, so not to put yourself into the danger of having to float all the way down, or dying.

The battle is alot of combo points, and darting of the eyes to watch the cool downs, attacks and health. Unless you are close to dying, don't waste the fight time by healing. It's pretty tricky to heal and fight at the same time.