This Epic Boss summons roots to assist him, and with his massiveness, he can deal some damage as well.
Defeating the boss for the first time will immediately unlock Dhaegon Stonecrusher
Even though he is the last boss, he still seems to be the easiest, at least within Normal Mode, mainly because the original campaign dungeons where designed before Runes were added. Additionally, as when at level 55 (the level required to play his chapter), with all the tools you have, it is very easy to make a comprehensive team. Mainly all you need is a fire team or at least just two fire elements.
Its the same as in normal mode but a lot more intense and more synergy needed.