Throne of Glass 8 books in 1

When magic has gone from the world and a vicious king rules from his throne of glass, an assassin comes to the castle. She is a prisoner, but if she can defeat twenty-three killers, thieves, and warriors in a competition to find the greatest assassin in the land, she will become the king's champion and earn her freedom. But the evil she encounters in the castle goes deep, and as dark forces gather on the horizon – forces which threaten to destroy her entire world – the assassin must take her place in a fight greater than she could ever have imagined.

This is the epic, heart-stopping fantasy series that has turned #1 New York Times