Yai Ayanokoji, known as Ayanokōji Yaito (綾小路やいと?) in Japan, and as Yai Ayano in the English anime and manga, is a student at ACDC Town's elementary school and also Lan Hikari's classmate and friend. Yai's NetNavi is Glyde.EXE, who's more of a butler than a fighter.
Moreover, Yai has skipped a grade in school because she is very smart. Her family is also rich and they live in a mansion in ACDC Town. Her father is the owner of the video game company AyanoTech (Gabcom in Japan, a play of Capcom). Additionally, Yai befriends Mary Towa in MegaMan Battle Chip Challenge.
Yai is very rich which makes her a bit arrogant and a showoff in the games and the anime. One example is when she refused school food and ate a steak instead. She also is a bit playful, shown when she turns on the booby traps in the garden around her house when Lan and Dex try to sneak in. Yai also likes to drink strawberry milk and collect different objects. She is very aristocratic in the sense that she doesn't hesitate to use her friends in the anime to solve her problems, such as when a virus stole the data for her new video game and when JunkMan.EXE took her space station.
Yai also has a crush on Chaud in the anime ever since he helped her out of a stopped elevator.
She makes a very flamboyant introduction into Lan's school in MegaMan NT Warrior. She starts off with a slide show and at lunch, she refuses school food and eats a steak. Lan and Dex sneak around her house, but get caught in numerous traps activated by Yai and Glyde. Later, she gets caught in traffic when Maddy and WackoMan attack the traffic light system causing a traffic jam. Yai, however, desperately needs to go to the bathroom and sends Glyde to investigate. Once traffic is clear, she gets to the bathroom.
She doesn't participate in the N1, but cheers her friends on and helps Mayl against Ms. Madd when she tried to cheat by blinding Ms. Madd with her forehead. In one episode of NT warrior, she follows Chaud during an intermission break in the N1 Grand Prix. She spies on him when he makes a business deal and gets caught. They both get stuck in the elevator and Chaud helps Yai climb out. Since then, Yai secretly adores him.
After the N1, Yai brings Mayl, Dex and Tory to the island that Lan is on vacation at. She exhibits a private jet, a submarine, and a veritable army of maids.
In MegaMan NT Warrior Axess, she spends a lot of time in Kingland. However, she once makes Lan and co. come to Kingland by sending out various errands by email to a specific location. Once there, a giant robot kidnaps them and transports them to Kingland. They have to find character data for one of her company's games and are taken to places that Yai likes. It turns out that the data is a replica of Yai's personality. They figure out that the data will be at another place that Yai likes and traps the virus carrying the data and retrieve it. She returns briefly in the battle against Nebula, but returns to Kingland in Rockman EXE Stream.
- A running joke in the anime, is that her forehead is so (big and) shiny, that she can use it to blind people temporarily. She actually uses it to her advantage and has even called her unique feature, her "charm point".
- Chaud has a tendency to make fun of her a little for it, and once got blinded himself, looking at her private jet in the sky while at a meeting.
- A certain story arc involving her in MegaMan Battle Network 2 created a degree of controversy with parents when she said that if they don't rescue her, they'll "miss the chance to see Miss Yai naked".
- Episode "Secret of the Ayanokōji House!" revealed that the Ayanokoji Family and the Ijuuin Family have been in competition since ancient times. Yai summarized it as a "love hate relationship".
- Yai has been revealed to be named after a little island girl named Yaito from Mega Man Legends 2. Interestingly, her Navi Glyde also is named after a character from that same game.
- She bears some resemblance towards the Megaman Legends character Tron Bonne, due to their fringes being similar and their hair arcing upwards in similar ways.