After you and Donan had made your way into the Eldhaime Barracks, you searched for Yorin and found out that Lilith had gotten to him first.
With the use of the blood petals, you discovered that Lilith stabbed Yorin with the Soulstone, granting Astaroth control over his body.
Donan still believes that there is hope to save Yorin and he has made his way to Cerrigar, expecting that you will meet him there.
How To Get Shadow Over Cerrigar Quest?
The Shadow over Cerrigar quest follows after you have completed the Entombed Legacy quest, where you previously discovered that Lilith has given Astaroth control over Yorin’s body.
Shadow Over Cerrigar Quest Objectives
1) Join Donan in Cerrigar
Donan has made his way to Cerrigar and you will need to meet him there to rally with the others who plan to fight back against the attackers.
2) Join Donan outside Lower Cerrigar
Donan will be nearby waiting for you along with other villagers who want to fight back and once you arrive, he will charge into Cerrigar.
3) Enter Lower Cerrigar
Head into Lower Cerrigar and a cutscene will begin where Lilith appears and taunts Donan, telling him that Yorin has been waiting.
It is later revealed that Astaroth has taken over Yorin’s body and has already transformed while also riding the Amalgam of Rage beast you fought previously.
Doran will collapse to his knees in shock and will no longer be able to help you further in the upcoming battle against Astaroth. (Quest ends here)
Shadow Over Cerrigar Rewards
Once you reach Lower Cerrigar and the cutscene where Astaroth is revealed is finished, the quest will be complete and you will be rewarded with XP and Gold.
After meeting up with Donan and the other survivors in Cerrigar, the retaliation was about to begin but Lilith seemed to have planned everything.
Yorin has been taken over by Astaroth and this has shattered Donan’s heart, making him incapable of fighting against his foes.
You have stepped forward during Donan’s breakdown and will lead the fight against Astaroth on your own, hoping that this inspires the other survivors to retaliate.