Complete secondary quests to gather allies from Skellige to assist Geralt, Yennefer and the witchers of Kaer Morhen in a battle against The Wild Hunt.
The Witcher 3: Brothers in Arms: Skellige
Between Va Fail, Elaine and The Isle of Mists it is in your best interests to gather allies. If you've been completing secondary quests as they arise this is no difficult task, but if not, you have quite the slog ahead of you.
There are three Brothers in Arms quests, one for each major region. Here are our recommendations for getting the job done in Skellige:
Crach an Craite
Crach an Craite cannot attend the battle, but will gift you with a unique sword to aid your efforts. Visit him in his keep at Kaer Trlde, or at the Coronation site (Gedyneith).
Cerys and Hjalmar an Craite
Whether Cerys or Hjalmar rules Skellige, Hjalmar will come to your aid in the battle ahead. To secure his services, you must have helped settle the succession by completing the following quests, then check in with both of the siblings:
Folan and Vigi
If you kept these two rascals alive during the Lord of Undvik quest, both will accompany Hjalmar to Kaer Morhen.
Ermion instantly signs up to your cause; he's a good 'un. Find him either at Kaer Trolde, or at the Coronation site (Gedyneith).
With these tasks complete you can attend to Brothers in Arms: Velen and Brothers in Arms: Novigrad, or if you have completed all three regions, go on to The Isle of Mists.