The Elden Ring Blaidd questline intertwines with several other important characters and activities, and it's easy to skip significant portions of it depending on where you travel to first.
It’s also tied with a difficult boss battle, but you can start the quest at any time – even if you’ve defeated Darriwil, the Evergaol boss that Blaidd mentions, before finding the wolf man in Mistwood.
What is the howling in Mistwood Ruins in Elden Ring?
Like most things in Elden Ring, starting Blaidd’s quest is a bit vague. You’ll need to travel to the Mistwood Ruins, northeast of Waypoint Ruins, and hear the howling. After that, travel back to the Church of Elleh in Limwood, and speak with Kale, the merchant. He’ll tell you about Blaidd and teaches you the Finger Snap gesture.
Head back to the Mistwood Ruins, and use the Gesture to summon Blaidd. If you’ve not defeated Darriwil yet, he’ll explain his relationship with the Bloodhound Knight and send you off to battle. After that, or if you’ve already defeated him, speak with Blaidd at the ruins again, twice.
The first time, you’ll get some Smithing Stones. The second time, he tells you to find the blacksmith on the road to Carian Manor in Liurnia. Doing this unlocks the Carian Filigreed Crest from that smith’s shop.
How do you continue Blaidd’s quest in Elden Ring?
From here, Blaidd’s quest joins with Ranni’s quest. After Ranni summons Blaidd, you’ll need to meet him in Siofria River near Hallowhorn Grounds (where the dead deer is). Speak to him until there’s no new dialogue, then travel to Seluvis’ Rise and speak with Seluvis. This triggers Seluvis' own quest - though it's not required for it, as you can start without even having met Blaidd. Take the scroll to Sellen in Waypoint Ruins, then speak with Blaidd again. This is completely separate from Sellen's own quest.
Now you’ll need to challenge Radahn in Caelid’s Redmane Castle. Use the NPC summons to make the fight easier.
The next leg of the quest is much longer and ties in with Ranni's quest. After Radahn dies, you'll find Iji, one of Ranni's servants, has imprisoned Blaidd in the Forlorn Hound Evergaol. He remains there until you've completed Ranni's quest, after which he'll turn up at Ranni's Rise and fight you. Defeating him earns you his sword and armor, and there's no way to un-aggro Blaidd.
Notes on Blaidd's and Ranni's quests
Ranni's and Blaidd's quests progress differently depending on the point at which you meet certain milestones. We've outlined some of the known ways the paths might differ below.
If you begin the Radahn Festival, you'll automatically skip the first part of both Ranni's and Blaidd's quests. Ranni's can only be progressed or begun after you defeat Radahn. Blaidd's will skip to the point of his imprisonment.
You can automatically trigger the Radahn Festival outside of Ranni's quest by using the Grand Lift of Dectus. If you do, Blaidd will defeat all enemies in the castle, and the castle's doors will be locked until after the Festival and you rest at a Site of Grace. It's unclear whether the same events unfold if you reach Altus Plateau via the tunnels instead, though.