Kai's Death

Kai was recently killed by the hands of Lord Garmadon. After a couple of months of the other ninjas grieving his death..reports have stated that an unknown person has been spotted in areas where the ninja fought Garamadon. The only strange thing is...that he always disappears when the ninja show. Who is this mysterious person? Read to find out.
I don't own anything from Ninjago..they belong to it's creator Tommy Andreasen and Cartoon Network.
I also don't own the photo used for the cover...it belongs to it's creator