Aquamarine

"Are you "My Dad"?"

- Aquamarine upon meeting Steven. "This is getting annoying. Hey, Topaz, can you remind me? I mean, my memory is perfect, but our orders were to bring back these six humans. I'm just not sure. Did they specify...alive? You know, I don't think they did!"

- Aquamarine revels she is willing to kill the hostages if the Crystal Gems do not stand down.

Aquamarine, known by herself as The Best, is a major antagonist of the Cartoon Network animated series Steven Universe and one of the main antagonists in the limited series, Steven Universe Future. She is a Homeworld Gem and high ranking court member who serves under Blue Diamond. Aquamarine, serve as the main antagonist of both the final four episodes of Season 4, and the first episode of Season 5. She reappears in Steven Universe Future, teaming up with Eyeball Ruby and form a fusion named Bluebird.

She was voiced by Della Saba.

Past
Little is specifically known about Aquamarine's past, but it is known that she and all other Aquamarines are high ranking soldiers who serve under Blue Diamond. At an unknown point (likely after the Crystal Gems defeated Holly Blue Agate and broke Greg Universe out of the Human Zoo), she and a Topaz fusion were personally assigned by Blue and Yellow Diamond to find and retrieve several specific humans.

Season 4
In "Doug Out", Aquamarine and Topaz are briefly seen at the end of the episode approaching Onion. In "The Good Lars", Aquamarine and Topaz are yet again seen at the end of the episode, this time approaching Sadie.

In "Are You My Dad", after Steven realizes that Onion, Lars, Sadie, and Jamie have all gone missing, he finds Aquamarine, who asks him if he is "My Dad". Upon not realizing that Steven is not who she is looking for, Aquamarine flies off before he can get any answers from her.

Steven then tells the Crystal Gems and Connie about Aquamarine and how she is supposedly looking for her Dad, confusing all of them, as Gems do not have parents. After splitting up, Steven and Connie manage to find Aquamarine in the woods, and, although Connie offers to help her find her Dad, she replies by angrily stating that she isn't looking for "Her Dad", but rather "My Dad".

As soon as Connie states her name, Aquamarine happily flies around and tells Topaz that she "found a Connie", revealing that Topaz has trapped all of the missing people inside of her body. Topaz soon reveals that she is actually a Gen Fusion, unfusing and refusing herself over Connie in order to trap her, and when Steven tries to attack, Aquamarine takes out her Wand, forms a bubble around Steven and slams him into a tree, knocking him out. As Topaz and her walk off, Aquamarine casually states that their job is so easy, Topaz really could've done it all by herself.

In "I Am My Mom", Steven tells the Crystal Gems about Aquamarine and Topaz, terrifying Pearl, who realizes that they were personally sent by Blue and Yellow Diamond to get humans for the human zoo. To make matters worse, Garnet and Amethyst realize that, should Aquamarine and Topaz reach their ship, Steven's friends will be gone forever since Navy stole their ship. Upon getting a picture showing Funland from Connie, Steven and the Gems head there and confront Aquamarine and Topaz.

The Gems try to get Aquamarine and Topaz to release Steven's friends. However, they refuse, revealing that Steven's friends are being captured because they were all on a list created by Peridot 5XG after Steven told her about his friends when she was still aligned with Homeworld, also unintentionally revealing that "My Dad" is actually Steven's father Greg, as he referred to him by that at the time.

The Gems then try to fight Aquamarine and Topaz, however, they find themselves unable to do so because of both Aquamarine's wand and the fact that the fight would endanger the lives of the humans. In a disturbing twist, after realizing how much they value the humans, Aquamarine states that Blue Diamond never said to bring the Humans back alive, and has Topaz attempt to crush Jaime's skull, forcing the Crystal Gems to back down.

In an attempt to save everyone, Steven then tells Aquamarine that he is "My Dad", which she initially finds suspicious, but soon shrugs off due to desiring to get off the planet as soon as possible. Aquamarine then starts to pilot her ship and prepares to fly back to the Zoo, however, Steven manages to use his Bubble Shield to blow apart Topaz and free everyone, frustrating her.

Just as Alexandrite manages to catch the ship and everyone (sans Lars) tries to jump to safety, Aquamarine uses her wand to freeze everyone in place and taunts Steven for his futile efforts. Knowing the that he has no other option, Steven confesses and reveals himself as the Gem who started the rebellion and shattered Pink Diamond, Rose Quartz, causing Aquamarine and Topaz to abandon their original mission and capture Steven instead, flying off to the Gem Homeworld with him, while everybody in Beach City except for Sadie believed that Steven is presumed dead.

Season 5
In "Stuck Together", Aquamarine taunts "Rose Quartz" by stating that shattering him isn't the worst thing the Diamonds can do to him, although Steven doesn't care, as all his friends are safe. Just then, Topaz finds Lars hiding inside the ship and Steven tries to call of their deal, however, Aquamarine doesn't care in the slightest and continues taunting Steven. Aquamarine then sends Topaz to fix a problem with the ship's engine. Later, Aquamarine flies down to see what is taking Topaz so long and becomes enraged after catching her in the act of trying to put Lars in an escape pod (as Topaz had overheard Steven and Lars confronting their fears and insecurities, revealing that she can speak and actually hates hurting others).

As Topaz tries to explain what she is doing to no success, Steven tells Aquamarine to confront her fears/insecurities, stating that she probably acts mean to compensate for feeling weak, which only infuriates her even further. Aquamarine fires her Wand, Topaz dodges and grabs a Gem-Destabilizer, slamming her to the wall and threatening to use the weapon on her, however, she asks Topaz if she is going to walk up to the Diamonds with her Gem in hand, causing her to break down and realize that she shouldn't have tried to defy the Diamonds. Aquamarine then gets back up and tells Topaz, should she remember to focus on their mission, they will never speak about what happened again, before arriving at Homeworld and delivering Steven and Lars.

Several Aquamarines are seen in "Legs From Here to Homeworld" and "Together Alone", although it is unknown if Aquamarine is among them.

Steven Universe Future
In "Bluebird", Steven meets a new gem on Earth named Bluebird. After Amethyst asks Steven to introduce himself to the gem, Steven feels threatened and believes that the gem is a fusion of Aquamarine and Eyeball Ruby.

The next morning, Steven discovers that Bluebird as about to drop Greg and revealed themselves that they were casted out to Earth for revenge on Steven as they unfuse and reveal themselves to Steven, much to his shock. Aquamarine grabs Greg by the leg and threatens Steven that he'll drop "My dad" unless he listens to her demands. Fortunately, Greg grabs Eyeball's chisel and cuts his hair off, prompting Steven to tell Greg to get inside.

Aquamarine and Eyeball struggle to fuse and Steven fights them, but they were able to fuse into Bluebird again and begin to kill Steven. Before Bluebird can attack Steven, Alexandrite shows up and stomps on Bluebird, Bluebird unfuses, and Steven asks if they okay. Aquamarine attempts to redeem herself, but successfully fools Steven as she and Eyeball Ruby fly off into the sky.

Trivia

 * Aquamarine's design is strangely similar to Pan-dora's.
 * It is unknown if Aquamarine's primary Weapon, her Wand, is actually a Gem Weapon or Homeworld technology, as she is not seen pulling it out of her Gem, but rather her hair.
 * The way her weapon functions is almost identical to Syndrome's Gauntlets in The Incredibles.
 * One of the Great North Gem Monsters is apparently an Aquamarine as well.
 * As stated above, Rebecca Sugar has referred to Aquamarine as "particularly important", implying that she will play a major role in a future episode, story arc or season. This is proven to be true, as a fusion between her and Eyeball Ruby appears in Steven Universe Future.
 * Aquamarine is one of the few antagonists in Steven Universe, who does not reform and she flats out reject redemption, alongside her partner Eyeball Ruby.