How to get this quest
Speak to Dolus in Main Cathedral in Verdeaux after meeting him there as the Arch-Cardinal.
Preparing the ritual
Before the ritual can start, you have to meet with the adventurers in Trademond's guild. You then get an optional objective. Accomplishing this objective will allow Desmond to be present in your party during the ritual. See Entertainment Magic for further details. Some jump points with an AGI check (or collar removal) will come during the ritual.
The Roland Popularity stat will also impact the difficulty of some enemies during the next section. If you plan to lower this stat, this is a good time to do so.
Once you are ready, go speak to Dolus to start the main event. A very high number of enemies inside the Goddess's domain are either resistant to Physical or weak to Thunder. So Lightning Blade is advised.
Heavenly Path 1
You arrive in the Goddess's domain. There are some mechanics exclusive to this domain:
The first fight inside the domain will be against Barry and Darry. The passage they guard will be freed whether or not you win the fight.
To proceed further, you will need to deal with an obstacle requiring either 20 Souldust or a collar removal. After this obstacle lies the first divine gate. There, another fight occurs. Barry and Darry join the fight if you lost to them when entering the domain.
Heavenly Path 2
To get past the second divine gate, the first three obstacles are identical to the one you dealt with to reach the first divine gate. The catch is that you also need to collect two orbs to actually proceed further. WARNING: Once you open the gate, you should make sure Remove Collar is available, because the next section will contain a battle where losing will lead to Game Over if Remove Collar can't be used.
One of the orb is guarded by Lysander. Roland is guarding the other one. To help fighting them, one of the red flame NPCs can offer temporary (one day duration) spells for a Souldust fee. Aura can't receive the spells. But, as long as you can pay the fee mutliple times, nothing prevents you to teach the same spell to multiple party members or teach mutiple spells to a same party member.
Lysander is a hard physical hitter when he uses Windup II and his Liberation abilities tends to make him hard to hit. The Poison and Blind states are interesting to use against him. Physical resistance and Pacify add a lot of survivabilty.
Roland's difficulty increases with his popularity. His mooks and himself use Lightning attacks, so resistance to Phys is useless. Like with Lysander, Poison and Blind are good states to use. Brighten is also advised because two of his mooks start with Shadowcloak. Furthermore, those two mooks start with the Exhausted state if you enter the fight with a nasty-smelling coating on.
Double battle
Once you enter in the last section of the Goddess's domain, the Souldust respawn ceases to apply and you will be given an opportunity to fully recover by interacting with the blue orbs.
Progressing will get you some cutscenes and after exiting the Labyrinth, you will get an alternating battle where the enemy you fight and the character you control changes each turn. Here are the battle's mechanics:
Note that removing Aura's collar will trivialize both parts of the battle because Star Shine acts on the other playable character.
Dolus uses his Truthmaker skill to transform his lies into truths. But, if he makes a lie attempt turning out to be a normally true claim, his claim gets invalidated, he becomes temporarily stunned and takes 1000 damage. He can make three kind of claims during the fight and cycles between them.
Claire uses the body of some monsters as armor. Once you defeat one of her armors, she gets stunned for two turns. You can use Desidia + Nightmare Claw during this time to do significant damage to her. Her armors are an ogre king, a golem and a behemoth. Desidia is useful against the behemoth to lock it to using a skill which does nothing.
Final battle
The quest's final boss can seem tough because Aura can't prepare after the prior fight. But you are offered another collar removal, which will automatically kick in if your party gets wiped.
Resistance to the Dark element is advised if you don't want to remove Aura's collar. Clairedolus will always start the fight with a buff followed by an attack, followed by a debuff that reduces willpower, blocks martials and spell for 4 turns, followed by a damaging spell.