Lessons for a Master

Spoiler Notes

 * Iron Baron is killed by Firstbourne.
 * The Oni Mask of Hatred is destroyed.
 * Nya does Spinjitzu.
 * Nya injures her shoulder.
 * The Dragon Hunters free the Ninja and Faith.
 * Faith chooses to stay in the First Realm.
 * Wu and the Ninja head home to Ninjago.