Tyen'sail is mentioned in Isabelle Duchamp's journal, where he is said to be a local elf, hired as a guide to find ancient elven ruins in Toussaint. In Adona of Carreras' journal, his armor-making skills are mentioned. Lazare Lafargue is said to have trained at his side.
In The Witcher computer game
The elven songmaster Tyen'sail took an interest in Raven's armour and worked for twelve days straight, each movement of his chisel accompanied by a song of power. It is said that the armour sang a song of victory for its wearer providing him with confidence and calm during battle. It is his notes that Geralt must find as one of the components required to re-make the famous armour in the Armor quest.