Mio Kuroki

In everyday life she keeps long, dark brown hair worn with bangs, paired with deep, shadowed eyes. Her royal incarnation is a different creature altogether. As Queen Mio she dresses the part of a Dark Kingdom sovereign, wearing a heart-accented striped bodice above a hot pink skirt, with black gloves, black stockings, and ankle-high boots. A fur-trimmed pink cape falls from her shoulders, she carries a wand capped with a skull, and her plush dog Choppi is seldom far from her side. The Valentine heart recurs as a motif across nearly every piece she wears.

The warmth Mio projects is a performance. Underneath sits a selfish, scheming manipulator, a trait rooted in her being the essence of Queen Beryl, and much of her cruelty is aimed with sadistic precision at unraveling Usagi. She fixates on stripping away whatever brings Usagi happiness, above all the girl's bond with Mamoru, and she even feigns romantic interest in him, once faking an injury so he would nurse her back to health. Cold enough to lie to Usagi's face and laugh only where she cannot be seen, she betrays what looks like genuine fear at just one moment, when Metalia Endymion strikes her down. A gifted fabricator, she twists and inflates the details of events to win sympathy or set people against one another, all while masking her true intentions.

Mio transfers into Usagi's class and instantly becomes the school's darling, though her standing as Minako's idol rival leaves Usagi conflicted. She detests Usagi and torments her through cruelties staged to look like accidents. Minako, who knows Mio answers to the Dark Kingdom, grows suspicious, as does Naru, and the two warn Usagi to stay clear of her. Her powers mark her as no ordinary transfer student: she can control minds and injure people telepathically, a gift she turns on Naru, and dark petals tend to trail in her wake once her true colors show. Rei eventually corners her over the harm she has caused and bargains for a day alone with Usagi in exchange for silence, a deal Mio accepts only if Mamoru can be talked into remaining with Beryl. Metalia Endymion then turns on her, and despite her screams for Usagi to help, he kills her at once.

She returns for the Special Act as Queen Mio, now able to mend and conjure objects out of nothing, breed monsters from flame, summon legions of Pierrot, and even copy the Four Kings of Heaven. After wounding Rei and abducting Usagi and Mamoru, she presses Mamoru to rule a new Dark Kingdom at her side and to kill Usagi, only for the Four Kings to remind him that Usagi is his soulmate. Repowered, Minako, Makoto, and Ami arrive to finish the fight, Mio warps into a plant-like creature, and her final form falls to the combined might of Sailor Moon, Mercury, Jupiter, and Venus, channeled through the Moonlight Stick as Sailor Planet Attack.