An

In her true alien shape An has pale green skin, hot pink eyes, and blue-tinted lips, framed by long soft-pink hair streaked with blue. She wears a form-fitting bodysuit and heels that echo Ail's outfit, and the two even trade palettes: her highlights match the shade of his hair while his match hers. Disguised as the human Natsumi Ginga she looks entirely ordinary, with peachy skin, shoulder-length red hair, and brown eyes.

Although she is devoted to Ail, An is seized by an instant infatuation with Mamoru and pursues him relentlessly, brushing aside his obvious unease. Like her partner, she treats romance as something to be seized rather than earned. She is a jealous hypocrite about it too, flying into spiteful rages whenever Ail so much as chats with another woman, once stomping Makoto's homemade lunch out of pure envy. Vain and cold, she counts herself and Ail above ordinary humans, looks down on the likes of Usagi and Makoto, and spares little sympathy for anyone she hurts.

An and Ail are the last survivors of an alien race whose lives all flowed from the Makai Tree. When their people grew greedy and turned on one another fighting over control of it, only the two of them remained, and the tree carried them to Earth hoping to teach its children love in place of greed. To feed it, the pair siphon energy from humans, with An slipping into the disguise of Natsumi and enrolling at Juban Public Middle School.

Passing Mamoru on the street in her first episode leaves her instantly smitten, and she spends the arc casting herself as Usagi's rival for him. Her schemes range from stealing energy when her own reserves run low, to cheating her way into the role of Snow White so she can kiss Mamoru during a school play, to babysitting a baby she believes is his, only to be driven off in disgust. Alongside Ail she deploys Cardians against the guardians while nursing her jealousy of his own flirtations.

The turn comes in the arc's finale. An shields Mamoru from the Makai Tree and, when it lashes out and impales Ail, throws herself into its path to save him and is run through by its branches. The tree, revealing it was never truly evil and only starved for the energy of love, restores her to life. Reconciled and finally grasping what love means, An and Ail leave together to begin a peaceful new life beside the revived tree. The two count among the earliest villains in the series to be redeemed rather than killed.