Bismuth was a one-shot character on Steven Universe, voiced by Uzo Aduba.
Bismuth was originally a builder for Homeworld, assigned to help construct the colony on Earth. After encouragement from Rose, however, she fought in the Rebellion alongside the Crystal Gems. She made all of the material weapons used by the Crystal Gems during the Rebellion and even took part in the fighting herself.
At some point before the war ended, she created the Breaking Point and presented it to Rose, who disagreed with the weapon and Bismuth's intentions with it. Bismuth, in a rage, attacked Rose under the belief that Rose 'left her no choice' and was poofed by Rose, bubbled, and placed inside of Lion's Dimension. Rose then hides the truth from everyone, telling them that she had lost track of Bismuth at the Battle for the Ziggurat.
Approximately 5,300 years later, Steven frees her from the bubble by accident. After regenerating, she was confused where all of the other Crystal Gems were. Bismuth was brought to the Strawberry Battlefield where she learned how long she was inactive for and that she, Pearl, and Garnet are the only known survivors of the rebellion still around in the present day.
Bismuth then shows them the Forge and how she makes weapons. Later, Bismuth attempts to present the Breaking Point to Steven. When Steven rejects the weapon as Rose did, Bismuth attacks him in a rage as she had tried to his mother, forcing him to impale her on Rose's sword and poof her before destroying the Breaking Point.
Steven came back to the temple and told the Gems what really happened to Bismuth before and what happened to her now, after which they put her gem in the Burning Room with the Corrupted and Cluster Gems while mourning their fallen friend.
In "Mindful Education", it is revealed that Steven is still traumatized from the events of "Bismuth" and feels guilty for being unable to help her, along with Jasper and Ruby (Eyeball).
Bismuth is boisterous, fierce, determined, empathetic, and emotive. She is not afraid to speak and act her mind. While Bismuth cares deeply for her friends, she also harbors an immense hatred for Homeworld elites - specifically the Diamond Authority.
Bismuth has an aggressive personality, even when being affectionate. When she sees her friends Pearl and Garnet, she immediately pulls them in for bone-crushing hugs. Her manner-of-speaking is blunt and to-the-point, and she acts without gaining consensus from the group surrounding her. She enjoys fighting: she reminisces fondly on the battles she and Garnet fought together against Homeworld's army, for example, and she loves to spar. When confronted, she attacks first and asks questions later. She has a playful side: she regularly creates puns out of the word "Bismuth" and habitually ribs the other Crystal Gems.
Bismuth is deeply devoted to her friends. She makes them weapons to complement their existing skill-sets; she playfully teases them while they are alive; and she grieves for them when she learns they are dead. The fact that the remaining Crystal Gems did not know of her imprisonment within Lion's Dimension troubles and wounds her.
Bismuth also relishes the freedom and possibility that results from being a Crystal Gem. She speaks with passion and wonder about Steven's ability to be himself (rather than a copy of Rose Quartz) and her own ability to differentiate herself from other Bismuths by doing what she wants rather than conforming to a prescribed role. Bismuth's passion for maintaining her own freedom and the freedom of others is what drives her to fight against Homeworld. She deeply resents the "Homeworld elites" for forcing her to do their bidding, and this resentment manifests itself in the form of unmitigated hatred.
Bismuth is vindictive and determined to win the fight against Homeworld at any cost. She has no faith in the leadership of Homeworld, whom she believes to be fundamentally evil, and sees it as her duty to free the gems that live under Homeworld's rule. Because of this conviction, she is willing to go to any length to obtain what she sees as justice. This mentality leads her to build the Breaking Point, which she sees as the only way to defeat Homeworld despite the ethical complications of using it. It also ultimately leads her to attack Steven with intent to shatter him, whom she believes to be Rose Quartz attempting to stop her again. When it comes to defeating Homeworld, Bismuth becomes ruthless and a danger to anyone standing in her way.
Bismuth has a large, bulky body type with broad shoulders similar to that of Jasper. Her head outlines the shape of the rest of her body, with a large jaw and noticeable cheeks similar to Steven. Her hair is styled in several dreadlocks in a mixture of several bright tones, all held back by a lilac headband. She has a periwinkle complexion, and she sports a single tattoo-like marking of a star pattern on her left shoulder in a smoky dark red. Her gemstone is located in the center of her chest and is noticeably concave.
She wears a black apron-like outfit, resembling a blacksmith, with a single brownish attachment and a pinkish-red star-shaped belt around her waist. Her pants are a burgundy color, and she has dark brown boots.