Amy is the triplet of NW and Roy. She is an "incomplete biogenetically enhanced human clone" like her noseless brother. Her powers are considered to be similiar to a White Mage, but she prefers to violently beat up friend and foe alike. She currently lives in NW's underground home.
When Amy and NW were infants and still in their development chambers a group of government agents kidnapped the two from their test tubes. Faced with the option of killing them, two agents opted for saving them and thus they were sent to an orphanage. NW was eventually adopted and a memory of having a sister became quite fuzzy. The same could be said of Amy, who had forgot she had a brother as life went on.
Amy was later adopted by a swordsman, who also happened to be the owner of a pizza place. He realized that Amy had a lot of frustration that she couldn't seem to put to an end, which led to her frequent violent outbursts against anyone she came in contact with, especially annoying customers. The swordsman tried to teach her the way of the sword in order to lessen the frequent outbursts and gave her the sword known as "Hana."
In NW:TID, Amy is warped to another planet because of Todd's doing. Thinking that she had only been brought to another part of Infinium Earth she applied for a job at a bar so that she could earn some cash for a bus ride home. She is later reunited with NW and Moy and later discovers that she is related to the both of them. She acted as a healer in the Soda Wars.
(Warning: The following contains spoilers.)
Amy is living in NW's house while her brother is off on an adventure across the universe. She still works for her father and seems to be as bad tempered as ever.
After trying to keep her cool when she encountered Ian, Amy let out her rage against Ian's landlord, who tried hitting on her and getting out of paying for his pizza.
When Ridaos and Arilean were observing a sleeping Ian, Amy knocked the prince out cold when he attempted to flirt with her. Unfortunately for Arilean she had plans for him too and tied him to the ceiling. She then promptly stuffed a pizza in Ian's face.
In the storyline "These Lovely Days" Amy confronted Liabelle and prevented her from running off with a sword that belonged to the prince. When NW came to her aid she promptly kicked him below the belt, showing no remorse for friend or foe.
Later she would save her brother from an uncontrolled Roy. NW was surprised at how powerful she was, but Moy pointed out that NW underestimates everyone. Amy brought NW back to their home and healed his wounds. Confused as to what just happened, Amy changed in personality to the point where she acted polite. She then allowed Duba to warp a drousy NW to Galsia.
It is assumed that she was killed in an "Unholy Rapture" that took place on Infinium Earth while NW was in Iwote.