" It’s no wonder you can’t see them,” replied Geralt. “Because they’re invisible. What, haven’t you heard the legends about witcher swords? The uninitiated can’t see them. They appear when I utter a spell. When the need arises. If one arises. Because I’m capable of doing a lot of damage even without them. "

― Andrzej Sapkowski , Season of Storms (The Witcher, #0)