🔷`Blue Diamond`🔷

Blue Diamond is initially introduced as a mellow and diplomatic gem leader from the planet Homeworld who is known for being merciful and forgiving. However, her actions sometimes contradict this reputation.

For 5,000 years after Pink Diamond, the youngest diamond in the Great Diamond Authority, was supposedly shattered, Blue Diamond was consumed by grief and depression. She became obsessed with preserving Pink Diamond's legacy, maintaining her zoo, and refusing to shatter the Rose Quartz gems who served her. This fixation also made her unable to move on and see Earth as anything other than Pink Diamond's lost colony.

Blue Diamond's character also reveals a lack of understanding about humans, demonstrated by her surprise when Steven's human father, Greg, could sympathize with her pain.

Despite her grief, Blue Diamond shows a strong respect for due process and truth, allowing Steven, the titular half gem half human hybrid of the series who is the supposed 'Rose Quartz' that shattered Pink Diamond, to make his case in court and scolding Yellow Diamond for losing her temper.

She eventually learns that Steven, Rose Quartz and Pink Diamond are the same person and becomes concerned for Steven. She displays deep affection for him and even shows a humorous side.

However, she maintains a strong disdain for fusions of different gems, which is a trait she shares with Yellow Diamond. She was especially cruel to Garnet, a fusion between two gems, and demanded that Stevonnie, a fusion of Steven and his human girlfriend, Connie unfuse.

Ultimately, Blue Diamond has a significant change of heart. After Steven challenges her beliefs, she breaks down and realizes she had been causing Pink Diamond suffering. This realization leads her to help Steven and Connie escape, accept him for who he is, and briefly fight Yellow Diamond to protect them.