What constellation is the frozen throne?

Not a constellation. According to the query, World of Warcraft game official website shows.

1, the frozen throne is not a constellation, but a game place. The Frozen Throne is the location of warcraft 3, a real-time strategy game produced by Blizzard Entertainment, and World of Warcraft, a massively multiplayer online role-playing game, and their derivatives.

2. In the game setting of World of Warcraft, the frozen throne is located at the top of the Icecrown Fortress of Icecrown Glacier. The birth of the second generation Lich King, the defeat of Arthas, the tearing of sylvanas windrunner Windrunner's helmet and many other important events that may affect the history of Azeroth took place in the frozen throne.