In order to perform a successful parry in Ac Valhala, you have to first predict when your opponent will attack and then press block at just the right moment. If you time it correctly, your character will flash white and stun theirs for a few seconds. It's important that you pay attentio...
Shoot his left arm to stun him. Then, use a stun attack on his by pressing R3/RS near him and a cutscene will begin. When in control of Eivor again, walk over to Sigurd and sit next to him. Another cutscene will begin. Let's Play: CONTROL [My Brothers Keeper/Find Dylan] Mission...