Originally Posted by
cynara
All three dragon pets are relatively straightforward in the sense that you have to avoid more or less obvious AoE and frontal cone attacks. Of the three, I found the Black Dragon to be the easiest to fight and its AoE attacks to be the least annoying.
The Undead Barachan Pirate seemed like a simple tank and spank fight, but he hits relatively hard. In any case, you need to be rank 4 in the faction to buy it, so it doesn't help you much while grinding towards rank 4.
The Risen Guardians pet (that you buy with T3 raid relics) is also legendary (even though the item from which you learn it is purple). I don't remember this fight well but IIRC the mechanics of the fight pretty much force you to kill the 3 mobs one by one while all 3 are hitting you. I found it a relatively inconvenient fight (but then I've only done it once so maybe it would get easier with more practice) and would recommend the Black Dragon instead.
(Note, I was only fighting these pets with a guardian, so maybe things look different from the perspective of some other class that is squishier but has higher DPS.)