The Warble of a Smitten Knight

Depending on the outcome: … He chose the pseudonym he used occasionally - Ravix of Fourhorn.

While playing knight, Geralt did not dare neglect his witcherly duties. He spied on Vivienne and followed her to a forest glade, where he discovered her secret. The woman had been cursed while still in her mother's womb. Touched by moonlight, she transformed into a bird.
Geralt offered to help her, to lift the curse that held her. Yet he warned Vivienne that the ritual to break the spell could have dire consequences.

Aided by Guillaume, Geralt performed a ritual that was to lift the curse from Vivienne and transfer it to another. Though the witcher doubted it could be effective, the rite worked and the curse passed to the young knight who had valiantly agreed to shoulder its burden. It brings a tear to the eye to think how a seemingly superficial fascination for a woman's beauty can take a turn even more beautiful...

Geralt performed a ritual aimed at reversing the curse that held Vivienne. He had warned her beforehand that it could result in shortening her remaining life to but a handful of years - the number lived on average by an oriole, the egg of which the witcher used during the ritual.
Vivienne had acknowledged this possible consequence and stated that she would be grateful to Geralt. For it was through his efforts that she could finally taste a normal life unfettered by the need to conceal her "defect."

Passed to Guillaume, the curse seemed much weakened, its symptoms far less powerful than those that had troubled Vivienne. When Geralt happened upon the couple some time later in Toussaint, they looked happy and in love. This only serves to confirm my observation regarding the unusual aura that seems to hover over the duchy. It almost inspires one to exclaim, "They lived happily ever after!"

Freed of the curse that had held her since birth, Vivienne resolved to take full advantage of life over the few years that possibly remained to her. A time after the events in Toussaint, Geralt happened upon the young woman in Novigrad. She had come there to visit this "largest city in the known world" and now sought a ship upon which she might sail to the Skellige Isles.

Tradition has sanctified two codes of conduct in Toussaint: the teachings of the Prophet Lebioda and the chivalric principles which guide its knights. These latter call for young men to prove their abilities through feats of daring during tourneys. One such knight, Guillaume, sought to stand out from the rest by fighting a shaelmaar and was injured as a result.

Afterwards, he pleaded with Geralt to visit him in the medics' tent. He said he had a very urgent matter to discuss.

Geralt was torn away from the tourney’s entertainments by the vampires’ attack. All able hands were needed to fend off this threat, meaning Toussaint’s menfolk could no longer dabble in artificial feats of bravery and staged fights.
Consumed by his battle against Dettlaff, Geralt had no chance to talk to Vivienne and never learned what secret she hid, assuming she hid one at all, and the whole affair was not just the product of a young lover’s imagination… These can be exceptionally fertile and prone to error, as I know very well myself, being both a lover and young, at least at heart.

Geralt came across Guillaume’s corpse in the city. It seemed the young knight had found bravely against the vampires before ultimately dying while defending his city.

Thus death won out over love, which unfortunately can happen even in Toussaint.
As I write these words I tip a glass of Est Est in honor of the poor young man… So what, that I didn’t know him -- Geralt said he was fine fellow, decent and true.
And that’s enough for me.