Butcher of Blaviken

The title Butcher of Blaviken is one of Geralt's aliases. Geralt gained the moniker after what transpired in the story The Lesser Evil.

In Blaviken, Geralt slew Renfri's bandits, as well as Renfri herself, in order to save the lives of innocent villagers. However, to the general populace, it looked like Geralt attacked them out of the blue as no one knew of Renfri's plans.

If Geralt resolves the conflict between two vineyards in the "Blood and Wine" expansion, the grateful owners create a wine in his honor, which can be named thusly.

During the quest "Troll Trouble", Geralt can intimidate one of Dmitri's comrades, forcing him to reveal the current location of Dmitri by mentioning that he is the "Butcher of Blaviken".

Achievements
There is also one Steam/Xbox Achievement called "The Butcher of Blaviken", which the player can earn by killing 500 foes.

This title follows the amnesiac Geralt even during the game, especially in the Temple Quarter of Vizima. Overheard in the quarter:

Also, if Geralt chooses to speak with the guards:

In the conversation with Toruviel at the Scoia'tael command post, she mentions to Geralt that he is the Butcher of Blaviken and that he "plowed Renfri before [he] killed her".

Der Schlächter von Blaviken Σφαγέας της Μπλαβίκεν Boucher de Blaviken Carnefice di Blaviken Rzeźnik z Blaviken