Blue Diamond

Blue Diamond is the minor antagonist of Cartoon Parody, and the secondary antagonist of the episode "Disney Channel's House of Villains" and the anti-hero of "Change your Mind".

She is a Homeworld Gem and a member of the Great Diamond Authority that rules over the Gem race.

Change Your Mind
Blue Diamond takes Steven and Connie to Yellow Diamond's Bubble Chamber to retrieve the Crystal Gems, to which Yellow Diamond questions what they are doing. Blue clearly states her intent to return the Crystal Gems to Earth, as they are happier there than they are on Homeworld. Yellow yells at Blue to take Steven and Connie back to the prison tower, but Blue refuses and the two begin to fight. While Blue and Yellow are distracted with their fight, Steven and Connie retrieve the bubble the Crystal Gems are contained in. Steven creates a bubble around him, Connie and the Gems as Blue and Yellow's fight causes them to break through a wall.

Yellow angrily yells at Blue, asking why she would hurt her closest companion and a fellow Diamond. In anger, Yellow attacks Blue with her destabilizing electrokinesis repeatedly until Steven throws his shield at her hand, causing her to stop. Steven yells that Yellow doesn’t have to fight, but Yellow refuses, rebutting that they all have to make sacrifices to appease White Diamond and maintain the "perfection" of the Gem Empire. Steven asks Yellow Diamond if this is what she would consider "perfect". Yellow analyzes the situation and realizes that doing this would cause everything that makes her happy to disappear, causing her to relent her attack and finally listen to Steven.

Steven secures the Crystal Gems to leave, wondering why they haven’t reformed yet. Yellow tells him that they will be out for a while, due to taking a direct hit from her destabilizing electrokinesis. Blue interrupts and tells them they have to leave before White finds out their plan. Yellow and Blue begin taking Steven, Connie and the Gems to the Pink's ship, but White Pearl stops them, menacingly telling Steven that he's "not going anywhere". White Diamond's ship then begins flying and connects with Pink's.

However, Yellow Diamond and Blue Diamond's ships, repaired and piloted by Bismuth and Lapis and Peridot respectively, attack White and knocks the ships over. Blue tells them to take one of their ships to escape to Earth, with Yellow insisting that they hold off White while Pink escapes. Steven refuses, saying that Pink ran away from them, then started a war with them, and states that it's time to finally just talk to them. Yellow and Blue attach their ships to the Diamond Mech, and Steven forces it to kneel and listen. Finally, with White Diamond's attention, Steven tells her that Yellow and Blue are unhappy with the standards she expects, of which Yellow elaborates that even though she does everything perfectly, it doesn't seem to ever be enough for White, and that causes a lot of stress for both Yellow and all the other Gems. Blue reminds White that they all used to be close and that Pink's seemingly meaningless actions were to try and keep them together and happy. Blue adds that though her purpose isn't to be happy, she finds it more difficult to enforce White's rules when they make her feel so miserable. Steven asks White once more to allow them inside her head to try and make a new beginning. White Diamond responds by firing beams from her eyes that completely remove the color of both Yellow and Blue Diamond, who then warp into the Diamond Mech.

Later, when the Gem break into White's ship, Blue and Yellow are still under her control. After Steven breaks through to White, she releases her control of them. They all then go to Earth to cure all of the Corrupted Gems, crashing Sadie Miller's concert. Here, they witness the arrival of Lars and the Off-Colors and after that brief interaction, they all come together at Rose's Fountain, healing all of the Corrupted Gems. Afterward, Steven waves goodbye to them, to which Yellow's arm on the Diamond Mech signals a peace sign, and they all go back to Homeworld, leaving Pink's Ship behind.