How do I play the Ult Amduskia?

Hi I'm pretty noobish at the game and am trying to complete the Tainted Origin Story quest and can't seem to figure it out online no matter how I search for it.

You have to have two classes at lv75.

If you mean to unlock it, then it requires that your main class and subclass both be at level 75 or above.

May just skip this story currently only level 48 so pretty far away from getting any class to 75 thanks though.