Captain Flash Sentry

Flash Sentry is a human male from the human version of Equestria. He is most known for being in the human MLP films as the "Waifu Stealer". After being put under the Siren's spell, he became overconfident, and yelled at Twilight, who was his girlfriend at the time. Once he was free of the siren's spell however, they broke up anyway for Flash being over-competitive.

He is then seen bullying the sirens for their villainy, only to be thwarted after Mango Mad abducts Adagio and Aria in an attempt to stop Sonata Dusk from taking over the multiverse. Since then, students have been disappearing, such as Sunset Shimmer, and Trixie. He would soon disappear afterwards as he was offered a chance at revenge against the sirens, and blaming them for Twilight and himself breaking up. The person who offered Flash Sentry this chance was the pirate ghost, Captain Salazar (From the 5th "Pirates of the Caribbean" film).

He then gathered up some students at the school, who would then become his crew, waited for the opportune moment to break the interdimensional barriers with the mirror, stole a ship, and set sail to get his revenge.

He then finds Adagio aboard a pirate ship of her own, accompanied by Mango Mad, who was flirting with her. The captain was outraged to see that her target now has a love interest, seeing as he lost his love interest to her. He then attacks Mango Mad and the pirate crew, ultimately capturing them. And then, right before Adagio's very eyes, Flash then mortally injured Mango Mad.