This is not as hard as I thought ….to get to graabak is easy I tried and tried to not fight him …..and found no way to avoid so instead I thought I would clear all sides 1st incase it changes any thing and finally i have it you NEED the serpent crown without it you do not get access to the dialogue options needed to get to the sun queen please read my partial solution to the "Nobody Expected This....." Achievement that will get you to the sun queen whoop her and take the serpent crown.....
Now when talking with "Grabaak" below are the dialogue options I chose:
i bear the serpent crown.
dost thou know how to destroy the crucible of souls.
thou knowest how to destroy the cauldron then.
thou choosest not to see at all.
where art this place.
thou art imprission here forever .
thou detroyest worlds for your own amusement .
what can i do so that thou wuldst tell me how to destroy the cauldron.
with the serpent crown i am thy equal.
i eased thy boredome.
.....DING!! all done
you can probably do it with less interactions but that is the way i did it