The Sandwich Guardians are a trio of giant ancient rock monsters who serve the purpose of protecting the three ingredients of the legendary sandwich. They appeared in "Legendary Sandwich".
Many years ago, a wizard built a legendary sandwich for the king of a kingdom and told him that the sandwich had the power to grant eternal life to whoever eats it. The king kept the sandwich safe in a glass dome so that it could be saved for when it was needed the most. One day, the prince got greedy and took the sandwich for himself and the king caught him in the act. He realized the sandwich wielded too much power and he had to send his knights out to the four corners of the Earth to hide every individual ingredient in different locations, where they would all be guarded by Sandwich Guardians. The bacon was hidden in a Lava Lake and guarded by a Sandwich Guardian. The lettuce was buried deep underground and guarded by another Sandwich Guardian. The tomato was planted on a distant planet in outer space and guarded by a Sandwich Guardian. Lastly, the pretzel bread was on sale at the grocery store. This ingredient was completely unimportant and obtained no magic or specialty to it, so the king never bothered to hire any Sandwich Guardians for the job.
In "Legendary Sandwich", Raven told the other Titans this story and they were all assigned their own parts of the sandwich to retrieve. Cyborg fetched the bacon, Starfire the tomato, Beast Boy the lettuce, and Robin was stuck with the dull and boring duty of getting the pretzel bread.
Cyborg flew to the Lava Lake and found the treasure. When he got there, he awoke the Sandwich Guardian, who punched him in the body. Cyborg fired a bunch of laser balls at him and the Sandwich Guardian threw a boulder at him. The Sandwich Guardian later grabbed his robot arm and ripped it off, angering Cyborg enough for him to fire a bunch of missiles at the Sandwich Guardian, blowing him into pieces, killing him. With the Sandwich Guardian dead and out of the way, Cyborg was able to get the bacon treasure and take it back home with him.
Beast Boy tunneled to the center of the Earth as a mole and found the second treasure with the lettuce. A Sandwich Guardian greeted him there and fought him off. Beast Boy tried to remain calm and talk things out with the Sandwich Guardian like friends, but the Sandwich Guardian crushed him between his hands, while he was in the form of a mosquito. Beast Boy transformed into a gorilla and was through being civil. Beast Boy bit into the Sandwich Guardian's leg, which shattered his teeth. He later turned into a whale and crushed the Sandwich Guardian to death under his weight and took the treasure.
Starfire found the tomato treasure on the alien planet but she was attacked by a Sandwich Guardian there. The Sandwich Guardian picked her up and threw her against a rock. When Starfire tried to fight him, The Sandwich Guardian took out a concentrated heat-based laser sword and fought Starfire with it. Starfire knocked the sword out of the Guardian's hand at first but the Guardian got it's sword back and chopped Starfire's hair off, which infuriated her greatly. Starfire used all her power to stomp on the head of the Sandwich Guardian, causing him to explode and die, allowing her to retrieve the treasure.
They are the first villains to appear in "Teen Titans Go!".
They have not appeared in the original series along with Ed, Carlos, and the Mockingbirds.
They resemble Cinderblock, because they're all big and made of stone, but gold colored and have red eyes.