Drauguria Legendary pokemon

*This is a fakemon*
Drauguria comes from the icelandic word "draugur" (ghost)
Drauguria is commonly refered as the "Ghost guardian"
It is a ghost/dark type, legendary pokemon.

STORY
As we all know, legendary pokemon do not evolve, but it is said in the legend that Drauguria guards a stone that reveals a hidden evolution of one of the legendary pokemon (not specified).

After a trainer has captured that one legendary pokemon and the bond with it becomes very strong, Drauguria will make an apparition.
After retrieving the stone from Drauguria's tail, the trainer will have the opportunity to capture it. If the trainer fails, Drauguria will vanish to the shadows to never be seen again.