In The Witcher 3: Wild Hunt
Tyen'sail is mentioned in Isabelle Duchamp's journal. He is said to be a local elf, hired as a guide to find ancient elven ruins in Toussaint.
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.