How to unlock Crystal Dragon? Crystal Dragon might not be all that bad after all. He would just obey the most powerful. Once you have defeated it in normal mode ("blue" side) and then in advanced mode ("red" side), you can use it like any other Monster.

To play with it, use this new Monster Board and leave its Boss sheet in the box. Like all other Monsters, Crystal Dragon starts the game with 10 hearts.

For more information, please refer to the BGG listing.