⚔️ The Wolven armor diagrams are in Kaer Mohern.⚔️ It has a level 14 requirement.⚔️ You'll have to fight a lot of wraiths to get it.⚔️ The upgrade diagram locations come from buying the notes from Éibhear Hattori in Novigrad, Lindenvale's armorer, Kaer Trolde's armorer, and the Hierarch Square armorer.
The Wolven armor is a medium set of witcher gear that functions as a bit of an all-rounder, buffing sign intensity attack power, and adrenaline point gain. It also has a passive that increases sword damage against bleeding enemies. It has four armor pieces, two swords, and no crossbow, similar to the Griffin set.
You can get the Wolven armor diagrams at the old signal tower just south of Kaer Mohern keep itself. There's a little puzzle involved in finding these, which I show in the video above, but otherwise:
Head inside, climb the ladder, and loot the chest to read Hieronymous's note.
Climb back down and use Aard to activate the teleportation crystal on the right side of the opening in the far wall.
Go back to the entrance and climb through the broken wall to the right, jump on the scaffolding on the north side of the tower, and walk along it to find the second teleportation crystal on a ledge to your right.
Go back inside and place the teleportation crystal in the housing on the left side of the opening in the far wall—use Aard to activate it.
Jump through the now-stable portal to land in a cave with a corpse. Defeat the wraith that appears and then loot the armor diagrams from the body.
Read the notes written in a shaky hand, which are also on the body in the cave, to unlock the locations of the Wolven Silver Sword and the Wolven Steel Sword diagrams, also in the Kaer Mohern area:
Wolven Steel Sword
In the Bastion directly to the west of Kaer Mohern keep, on a body in one of the burnt shacks as you enter. Prepare to fight wraiths.
Wolven Silver Sword
In the Ruined Watchtower to the north of the keep, along the west side of the lake. The enhanced steel sword diagram is also here. Prepare to fight more wraiths.
Once you've crafted the basic armor, you can upgrade it to enhanced, superior, and mastercrafted by finding the relevant diagrams.
Enhanced: Buy the well-preserved notes (boots, armour, silver sword) from Éibhear Hattori once you complete the Of Swords and Dumplings quest. You can find his home northwest of Novigrad's Glory Gate. Then buy the slightly torn notes (gloves, trousers, steel sword) from Lindenvale's armorer to the east of Crow's Perch in Velen.
Superior: Buy the damp, moldy notes (armour, silver sword, steel sword) from Kaer Trolde's armorer in Skellige. Then buy the heavily faded notes (boots, gauntlets, trousers) from Hierarch Square's armorer in Novigrad.
Mastercrafted: Buy the worn out and faded notes (armour, silver sword, steel sword) from Éibhear Hattori and the notes on parchment (boots, gauntlets, trousers) from Kaer Trolde's blacksmith.
🦅 Griffin: A medium set for signs🐈⬛ Feline: A light set for glass cannons🐻 Ursine: A heavy set for high defence
For grandmaster, when you head to Toussaint in the Blood and Wine DLC, speak to Lazare Lafargue in his armor shop in south Beauclair to start the 'Master Master Master Master!' quest to find the diagrams.