Ms. Madd made her first appearance in the first Mega Man Battle Network game. She first appeared during the event of IceMan.EXE freezing the water in the waterworks, where she pretended to be a worker at Scilab and told Lan Hikari to go home (due to closing time at Scilab). She is later found out by Lan that she was the one blackmailing Dr. Froid into freezing the waterworks system with IceMan (it could also be assumed that she kidnapped Dr. Froid's son); however, despite this, she had already obtained the aqua program the organization needed.
Ms. Madd later reappears in Den City, this time trying to sell a program that can resist malfunction (she and ColorMan cause the malfunctions). However, her plan was ruined by Lan. Madd then attempts to cause the bus that Mayl Sakurai was riding in to crash in retaliation for Lan ruining her plan. Still, her plan was ruined once again and she then attempted to blow up the bus, but Lan and MegaMan defeat her in the end.
Ms. Madd is later seen again near the end of the game along with the other WWW members, getting scolded by Lord Wily.
In this game, Ms. Madd is a normal contestant that will eventually be beaten by any one of the playable characters.
Maddy is a member of WWW and still operates ColorMan.EXE (WackoMan.EXE in the anime), however, her missions are less threatening than in the game. Maddy uses WackoMan to cause a traffic jam, however Yai Ayano desperately needed to use the bathroom and was stuck in traffic. Lan sees her in trouble and escorts her to a bathroom, with the aid of his roller skates. MegaMan was left jacked into a payphone, and manages to defeat WackoMan. Maddy is seen frustrated at a payphone parallel to Lan, leaving him confused, as he did not know Maddy was the operator of WackoMan.
Maddy, Count Zap and Mr. Match are later scolded by Lord Wily, but they manage to come up with a scheme to wreak havoc by releasing robotic fish at the aquarium. They watch from the WWW base as their plan wreaks havoc, but also as MegaMan and Lan foil their plans again.
After the foiled robotic fish scheme, Maddy uses Tory Froid to contaminate DenTech City's water supply. She controls him by holding his father captive and forces Tory's NetNavi, IceMan into freezing the water system. She watches over Tory as he does her dirty work and fights MegaMan. But, when the water is nearly contaminated, Tory decides to fix the damage. Ms. Madd locks him inside and tells WackoMan to delete IceMan. But, Lan helps MegaMan win and foil her plans.
Maddy later participates in the N1 Grand Prix with Mr. Match, Count Zap, and Yahoot; but is defeated early on by Mayl and Roll.EXE. She later re-enters by rigging the lottery to determine two returning competitors. She fights with Mr. Match against Lan and Mayl in a tag team match. Their in-fighting causes them to start out losing, but gain the upper hand when a rigged Battle Chip causes Roll to turn on MegaMan. Luckily they manage to reverse the effects of the Battle Chip and defeat WackoMan and TorchMan. After the WWW is disbanded when Lord Wily goes missing, Maddy is sent by Yahoot to look for Count Zap. After finding him, they start a curry shop to make a living.
During part two of season one she was hired to be part of the Netmafia Gospel by Gauss Magnus. She is given a gift by Yahoot in case she would ever want to return. However, despite liking it at first, she decided to quit when she realizes how Gospel is going too far. Later she returns to the curry shop and it turns out the gift was a coupon for a free bowl of curry.
Ms. Madd/ Maddy is tall and slim. She has small black eyes with purple eyeshadow and orange hair tied in big fluffy bunches at the side of her head and a spiky fringe at the front. She wears an orange and white t shirt with ColorMan's logo on the front over a long sleeved maroon shirt, blue, green and purple striped trousers and orange trainers with white laces. She also wears small silver hoop earrings in her ears.
- It was never explained what happened to her in the games. She may have been arrested like Count Zap or changed carrier like Mr. Match.
- In the anime, Maddy mentioned that she is 23 years old.
- She hates being referred to as "old".
- In the anime, Maddy's pants are sometimes jean shorts with colored socks, but the socks are sometimes connected with the jean shorts and become sweatpants.
- In the anime, Maddy is the only World Three member who was hired to become a Gospel member.
- In the English dubbed anime, Maddy's bikini is altered to hide her breasts.