Full Name: Ami Mizuno
Sailor Designation: Dark Mercury
Weapons: Dark Sword
Gear: Dark Jewelry Star Bracelet, TeletiaS

The Sailor Senshi began drifting apart after Sailor Venus revealed herself as the 'Princess,' and the senshi began to keep secrets from one another. Kunzite took advantage of the discord and caught Ami alone. When the team begins to drift apart, Ami became anxious. On her walk home, Kunzite confronted Ami in a moment of vulnerability and was enveloped by purple-black energy and left her unconscious. Makoto goes to Ami's house when she doesn't go to school and finds her sick in bed. After she feeds her, Ami convinces Makoto to go to the carousel, where she passed out. In Act 21, Makoto and Motoki took Ami to the hospital, where she disappears in black petals. Sailor Jupiter fights Kunzite, who has Ami and when Mars and Moon arrive, Ami's Henshin Bracelet was changed, and she transform using the phrase 'Dark Power, Make-Up.' Sailor Mercury was infused with the power of Queen Metalia by Kunzite and turned evil.

She wields a sword fashioned from an icicle, which she creates herself the first time her transformation is displayed. This causes drastic personality changes as well as the alterations to her uniform. She is self-confident to the point of egotism. Evil Ami, dressing predominantly in black, tends to move about slowly and sadistically, and when confronting the Senshi gives a sense of sadistic glee. Ami even brainwashed all the students at Juuban, including Naru to antagonize Usagi. Despite these alterations, certain aspects of the real Ami still remain. She still wants to do well in school, and wants friends, hence the brainwashing of her classmates.

Dark Mercury had no intention of being a follower to anyone, and was always trying to pursue her own agenda, which is to kill her former friends and become as strong as possible. She shows blatant disrespect towards Kunzite and even to Queen Beryl, perhaps because, unlike even the Shitennou, she had been directly exposed to Metalia's power during her conversion, as opposed to having Queen Beryl or someone else filtering it. While in the Dark Kingdom, Dark Mercury demonstrated kindness towards a very distressed Nephrite. She seemed to have a bit of a soft spot for him, despite her occasional jab at him. She even repaired his cape when it got damaged in a fight between he and Kunzite. She stated that she doesn't like to see him alone.

Dark Mercury spent much of her time attempting to destroy Sailor Moon. Mars, Moon, and Jupiter were reluctant to attack their friend, as dark as her powers had grown. Sailor Venus believe it was their duty to fight Dark Mercury, but they were still reluctant. Sailor Moon frequently attempted to heal her friend with the Ginzuishou. This allowed "normal" Ami to emerge temporarily. Unfortunately, Mercury is always snatched away before it could be completed, but it has some effect, ultimately resulting in her recovery. Dark Mercury having defeated Sailor Moon in battle in Act 28, but the trauma of seeing her injured friend due a near fatal blow caused her to realize she cares about Usagi, and to remember who she really is. Enraged at losing his pet, Kunzite tried to kill her but was stopped by Nephrite, as a favor for repairing his cape. After being healed, she didn't recall anything she did as Dark Mercury. This haunts her, as she becomes terrified of what she may have done to her friends, even though it wasn't under her control.

NOTES: In promotional photos prior to her premiere and even in an initial DVD cover design, she was shown with a different harp-like bow weapon. It never actually was used by her in the series but it was redecorated as a dagger for Zoisite. The series production staff nicknamed her alter-ego 'Akumi,' meaning evil beauty. She was also nicknamed Darkury by staff and fans.