Protector - First build the Keeper Protector at the Kino Der Toten construction altar.
Kills - Survive until the Keeper get around 15 kills and once it does there will be an audio queue.
Mask - Go to the stage of kino Der Toten and you can collect the mask on a mannequin. The benefits are +1 hit from zombies, 50% damage reduction from enslaved keepers, player does 33% more damage to enslaved keepers, keeper protector lasts 30 seconds longer. You will also get the perma perk of Juggernog.