Tempest Shadow is a scarred Unicorn from Equestria that first appears within Season 8 of My Little Universe. Her eye is scarred, and her horn is missing, and she is one of Grogar's commanders. She also seemingly is under the Storm King's command, referring him as "his excellency".
Tempest Shadow is shown as cold, calculative, and merciless towards others, not afraid to use force or even lethal violence in order to accomplish her tasks. And she is not above threatening death or taking hostages in order to do so, such as manipulating two of Canterlot's guards to capture Twilight Sparkle, or to use said Alicorn as hostage to stop Garnet.
Although as cold as other commanders of Grogar's Army, she is shown to be more professional and less cruel and sadistic. This is hinted at first when she insists for Peridot to not be marked as she was already damaged before Trotter could get her. This is shown more in full with her relationship towards Twilight, Twilight saying she's better than the rest in Tambalon, and the nicest one there.
Her backstory is briefly described during Season 9: when she was very young, Grogar found her starving and gravely injured with her horn broken, and since no one else was willing to help her, Grogar took her in and saved her life.
Her first appearance was when she arrived in Homeworld with the Storm battalion in order to retrieve Twilight Sparkle and take her captive prior to the takeover of Homeworld. She was discovered by Garnet during the retrieval. Upon this, she commands her troops to kill her, her eventually joining the fight. Seeing they won't win through force, she takes Twilight hostage and threatens to kill her if they continue to retaliate, the threat enough to make Garnet stop. Seeing she gained the upper hand, she uses her magic to split up Ruby and Sapphire. She then warns them both about Grogar's assault onto Homeworld by telling Sapphire to check the future, making her and Ruby leave her.
She briefly reappears when Flint, Pearl, Peridot and Emerald were brought into Diamond City, observing them being marked. During this, she insisted that Peridot avoid the procedure, as Cerrosafe told her about Peridot and that she technically had already been marked.
Throughout Twilight's imprisonment, Tempest Shadow was the only one that tried keeping her alive within Tambalon, even retaliating against higher ranking captains like Nichrome as she threatened to fight him if he tried tormenting anyone else again. During the season finale, Tempest was amongst the others when Flint and Amethyst tried to "join" Grogar's army. During their interrogation, she was the one in charge of questioning the two, and by the end she was assigned to instruct the two in Tambalon's laws. After showing them around, she left them in their quarters as she had a patrol to supervise, but warned them not to leave as they were on probation. However, after eavesdropping on them she did find them out, but didn't reveal it right away, allowing them to continue.
Sometime later, she was called in by Grogar to gloat about Twilight, Tempest herself remarking that Twilight had no way out and "no friends". When pointed out that she was a Pony like Twilight though, she brutally retaliated, saying she's nothing like her. Sometime later, during Ruby's distraction on Grogar, Tempest found the Harmony Gems trying to free Twilight, but Pinkie Pie tied her up and used her as a decoy. She managed to get herself free though just before she was called to Twilight's execution. Twilight gives her her thanks, and hoped she'll find what she's looking for.
Just after the fight, she reappears on Earth by the Barn House, alongside Budgerite and Bray. She informed Steven that he had no place back home, as he was a monster for "killing" Grogar and Garnet out of pure rage, and that killers only belong with other killers.
Tempest reappeared in Beach City again to confront Spinel in private. During her conversation, Tempest removed Spinel's metallic device, saying that her "actual friends" weren't planning to do that and they couldn't be trusted, all as means to have Spinel join Grogar's Army. After she succeeded in that, unbeknownst to Grogar, Tempest went and found Steven, Connie and Priyanka Maheswaran on the night before the attack, checking to see if they were alright, and telling them to stay away as she didn't want to see them suffer anymore because of him. After hearing them refuse her, she then tells them Grogar grew weaker, but then remarks that he'll kill them anyway before leaving.
Sometime later though, she went with the Storm King to invade Canterlot, with her coming out first and demanding that they surrender nicely, or they "make it difficult". She openly shares her disgust with her own kind, questioning why the princesses would stand up for ponies who can't stand for themselves. During the fight, Tempest Shadow battled against the Mane Six, which eventually resulted in her falling into Canterlot's river with them, knocking her unconscious for a brief time. She woke up downriver with the rest, and the Mane Six try to convince her she's on the wrong side, but Tempest didn't want to hear it. Being too tired to fight, she left them but not before telling them Grogar had nothing to do with the Canterlot attack. Shortly after this, she was found by Grogar, and she admitted to letting them go. This assurance in her loyalty got her promoted to Captain of Tambalon's Army.
Overtime, she continues to remain loyal to Grogar but shows more doubt in her own decisions due to the ram's questionable morality. Once Grogar is gained of his god status, he awards Tempest with her horn as he promised. However, during the final battle in the Realm of Corners, she ultimately decides to turn against him, and tells Grogar that she would rather lose her horn than lose her mind, destroying her horn doing so. She is ultimately spared by Grogar however despite this. She appears later in the Earth Moon Base with the remaining Storm Creatures of her platoon, forgiven of her past attacks and her apologizing for her actions. She was last seen in the Moon Base, safe with the others.
Tempest has been shown a high skill in physical combat, strong and coordinated enough to be a challenge towards the Fusion Garnet.
Being a Unicorn, Tempest is naturally capable of using magic. However, due to her broken horn, her use of most magic is severely limited, yet she turned this into a strength by using her electrical charge as a high-powered taser, strong enough to split fused Gems. For a brief time she gained all of her magic back when given her horn by Grogar, but she destroys it soon afterwards to defy Grogar.