Windcaller Kieldia
Elementalist with Earth’s embrace (utility and traited) and berserker gear seems like a logical choice. Maybe focus for the invulnerability if you think you’ll need it. I vaguely remember beating her on my ele, but that was a year ago so I’m probably not much help. Hated her though, took a while.
EDIT: Norn alternative: https://www.youtube.com/watch?v=vmFiSdT9HbU
(edited by Zomaarwat.3912)
Stability is more or less essential for beating her. I used my Ranger to kill her (RaO ftw!), but you might be able to get away with it by dropping lots of DoTs on Kieldia and doing your best to juggle Tornado and Armor of Earth if you get cornerd by the tornadoes.
I saw a Guardian beat Kieldia last night basically through luck as the tornadoes mostly hung out on the other side of the Arena.
I did it an my necro so it’s not nearly the same thing but my advice would be to go through utilities(i have an ele just not 80 yet), mist form should help to get you out of the whirlwinds but you might want to look for something that gives stability. Use those only if you start to get juggled, until then keep hitting her with burns and such. As for weapons i would recommend the Sc/D against her, try your best to keep b/w the (imagining the field as a dartboard) 2x and 3x areas as it gives you room to be bounced AWAY from the wind not juggled by it and give as much of a dose of fire as possible, healing with water when necessary. (For this fight you may want to set the healing signet as the others seem to do very little from what i have seen, of course if i’m forgetting a better one for this situation plz forgive me.)
A general tip is summoning an ice bow before you enter. Freeze her as soon as the fight starts, then summon a hail storm on her. If you’re full zerker this should deal 30-40% of her max hp. That’s how my friend finally did it on his ele.
Did the fight again today, berserker gear S/D, Sylvari take root elite, Arcane shield, Fire/Air signet, earth’s embrace. Specced to max in earth (stability on switching to earth) and fire (standard dmg traits), and 2 in water for reduced cooldown on cantrips. If you can get some condis on her you still do dmg while CC’d.