This page of the Assassin's Creed Valhalla: Wrath of the Druids guide contains a detailed walkthrough of The Cost of Betrayal main story quest.
Flann faces pressure from a council of Irish kings - he must decide what will happen to the Children of Danu.
Reward for completing the mission: 1,700 XP.
Travel to Durrow
Upon returning to Durrow, you will witness a conversation in which the kings demand that Flann eliminate the Children of Danu. When asked for your opinion, answer as you like, as it will not affect Flann's decision.
Talk to Ciara
Ciara will be clearly unhappy with her king's decision and will leave the meeting without a word. When you go to her hut and try to talk to her, Ciara will say that she cannot let the Children of Danu be killed, she will use a smoke screen and disappear.
Defeat the warriors
Follow Flann to Tara. When you arrive, you will meet Ciara, who has begun to draw power from the obelisk, apparently preparing for battle. Thanks to her magical abilities, she managed to take control of the king's warriors and put them in battle against their ruler. After a short cutscene, 8 elite units will set off towards you.
A bow or shield will come in handy while fighting multiple enemies. If you are fighting with other weapons, avoid enemy attacks and make quick counter attacks.
Ciara's immense power has enabled her to take control of Flann. The king has two weak points, one on the left wrist and one on the right shoulder - hitting these points will stun him and allow you to deliver a powerful hit.
Flann is not an agile opponent, so stay out of range of his two-handed sword. Attack him from a distance and you should be able to defeat him quickly.
Ciara is the final boss of Assassin's Creed Valhalla: Wrath of the Druids. The fight has been divided into two stages.
First phase of the fight
Ciara has only one weak spot, which was placed on her back. The best opportunity to stun Ciara will come when she starts doing pirouettes. Hitting this point allows you to unleash a powerful attack that will deprive the boss of up to 1/4 of her health points.
Most of Ciara's attacks are indicated by a yellow rune flash and can be blocked. However, watch out for the teleportation ability, after which Ciara brings out a quick slash with one of her short swords.
Ciara can also unleash unblockable attacks, which are indicated by a red rune flash - these absolutely have to dodged.
Ciara can use the power of the obelisk to regenerate lost health. As soon as you notice that she wants to use this ability, approach her and launch an attack to interrupt the healing effect.
Second phase of the fight
At the beginning of the second stage, Ciara will summon some Druid spirits who will draw power from the obelisk. You must eliminate them as quickly as possible - if you fail, Ciara will unleash a powerful shockwave that can do a lot of damage.
At some point, green circles will start to appear in the arena - when you stand on them, Eivor will take damage. Try to stay as far away from the contaminated area as possible.
When you deprive Ciara of most of her health, the woman will fall to the ground and you can perform a stun attack to end the fight.
After the fight, Ciara will beg for death, and you will be able to decide what happens to the defeated druid:
- An honorable death: Eivor says that this sacrifice will honor the gods of Ciara, then delivers a swift blow and kills the druid. In despair, Flann grabs his sword and destroys Tara's obelisk;
- I can't kill you: Eivor says that the source of the problems is Tara's obelisk, and it should be destroyed. Ciara is not convinced at first but eventually agrees and destroys the obelisk with her own hands. Flan apologizes to Ciara for letting her and the Druids in Ireland down and promises to make it right. Ciara says goodbye and walks away in a direction only she knows.
After the cutscene, the Cost of Betrayal quest will end and you will receive 1,700 XP as a reward.