The 3D version of the game couldn't run with Wakfu so it was removed.
Here is the full post.
"This switch to the 3D means many technical restrictions and changes will occur. The major, being that you will no longer be able to play Krosmaster Arena from WAKFU itself.
As a result:
- You won’t be able to use the Krosmaster Collection in Wakfu.
- The in-game Krosmaster’s quest will be removed from the game.
- The Krosmaster items machine will be removed from the game.
- You won’t be able to loot any Krosmaster Blind Boxes from within the game. "