Et bien tu dis :

Tank agro her far away of the stone.

quand les add pop :

tu dis kill the add fast, and the tank must take her allway away of the rock.

when her will launch her awesome AOE, two choice, every rock are intact, so you can hide behind one (everyone hide on this one) so the healer can heal everyone, immediately after this.

Or the tank use his limit break lvl 2, to make everyone imune to a lot of damage, prevent you to die, and go the final fight.
To the final fight only two thing to know. Mistral sing = a linear attack, go behind her, no one will take any damage.

Where her out of the circle to launch a linear attack, you must step back in the circle, far away the more you can from her, that will prevent you take any damage.

And now you can kill her good luck !

Voila ça devrais suffire !