Noonwraith mutagen is an alchemy ingredient in The Witcher 3: Wild Hunt and is used to craft noonwraith decoction. They act like lesser green mutagens when placed in the diamond-shaped slots in the character panel.
Like all special mutagens they can only be dropped by their corresponding monster. This one however, is the easiest and earliest that can be obtained in the entire game, through the Contract: Devil by the Well quest in White Orchard. If for some reason you wish to skip that, there's also the The White Lady outside Novigrad, and any regular noonwraith is guaranteed to drop it as well. You can even just wait for daytime if a nightwraith is encountered somewhere, and it will be swapped out.
Notes[]
- In an undocumented change for Patch 1.08, all mutagen icons were changed. However, there was still a bug for those on Steam and Origin that didn't reflect this and was later fixed in Patch 1.22. Despite this, some may still see the original icons instead, even with a fully patched game.
- This mutagen can technically also be dropped by plague maidens, if any such could be killed. However, the Pesta during A Towerful of Mice is the only such monster in the game and she is scripted to escape or be freed, never slain.