Knight Bernahl Questline

Quest Step	Location (Click for Map Link)
Bernahl can first be found at the Warmaster’s Shack on Stormhill, you can speak with him here and he will sell you some Ashes of War
After arriving at Volcano Manor speak with Tanith and join the manor, Tanith will give you a key to the Study Hall, Bernahl can be found inside this room
After completing two Volcano Manor invasion quests return to Bernahl and he will give you a request. This request takes place in Leyndell, from the West Capital Rampart head out and then immediately down the stairs in front of you, go around onto the balcony and you should see a large building, head inside and interact with the red summon sign to start the invasion.
Return to Bernahl in Volcano Manor and speak with him. Now you need to complete all the Manor Request and then speak to Tanith, after this she will teleport you to Rykard’s boss fight, defeat him and then speak with Bernahl once more.
When you arrive in Farum Azula you can summon Bernahl to help with the Godskin Duo Fight. To finish Bernahl’s quest you to get to the Beside the Great Bridge Grace, from here head up onto the bridge but turn around and go north down the bridge away from the Boss arena, follow the path through the building and down the ladders, there is a large building containing a chest just ahead of you, as you approach Bernahl will invade you, defeat him to get his Armor set, a Legendary weapon and finish his questline