From Nookipedia, the Animal Crossing wiki
Redd (つねきち, Tsunekichi), also known as Crazy Redd, is an untrustworthy kitsune, Japanese for fox, who runs Crazy Redd's, an illicit furniture store in the Animal Crossing series, where he is known to sell counterfeit paintings and over-priced items. Certain items sold are considered "special" Redd items. These items also have an HRA bonus.
He considers Tom Nook as competition, referring to him as "that raccoon in an apron." His unique passwords suggest he is 35. His symbol, the leaf of the Ginkgo Tree, is Redd's way of copying Nook's more recognisable leaf symbol. His stores tune in Animal Crossing was Nook's Cranny's theme in opposite pitch (when there was a high note in Nook's Cranny, a low note would be in Redd's Tent, and vice versa). It also used the same instruments. Additionally, in the Japanese release, both of them are members of mythical species from Japanese folklore (Nook is a tanuki and Redd is a kitsune).
 Redd's Profession
Redd owns a small business that makes most of its profits by over-charging its customers. Unlike Tom Nook, Redd charges for admission into his shop and asks for invitations, and tends to pressure players into buying his wares by concocting stories and lying about his products. Redd is rumored to have been involved in a large-scale insurance scam, with Lyle in Animal Crossing: Wild World.
In Animal Crossing, Crazy Redd owns a tent suspiciously labelled the 'Black Market' - the 'Black' being crossed out clumsily. His name could be a reference to this, making it the 'Redd' Market (red market). When he shows up in town, Redd sends the player a letter telling them the date at which he will arrive. On this date, the Player will have to wander around town until finding him in a random spot. (or ask Copper) He sells paintings, which can be donated to the museum. Some are counterfeits, others are real.
In Wild World, Redd appears once a week on a specific day of the week, which the player can choose by talking to Lyle, and sets his tent up outside the Town Hall. On this date, Booker will inform the player about Redd's arrival. On the first week of his arrival, the player will not know the password required to enter, and so will have to ask the villagers. A random villager will have the password, not necessarily the closest friend of the player. After reciting the password correctly to Redd, the tent will open and allow the player in. The player will then be asked to pay 3,000 Bells in order to use his store. If they do not agree to this, the player will not be allowed to purchase anything, and will have to inquire with the villagers next week for another password.
Once the player becomes a member of his "family", Redd will send them a weekly letter, received on the day before he arrives, with a new password.
Redd appears to be in cahoots with Lyle the Insurance Salesman - they work together to try and scam as much money out of players as possible. After the player speaks to Lyle about Redd, Redd somehow knows the day of the week when he should come to the town, which matches with the day the player selected when talking to Lyle.
In Wild World, Redd's age is implied by a password to be 35.
Redd has a sneaky and sarcastic personality, and when the player leaves his store without buying anything, he will say 'thanks a lot...' sarcastically.
In City Folk, Redd owns a small shop on the left of the city, in what villagers call a "dark alley". To get into his shop, a villager or friend would need to send an invitation to the player. This replaces the secret password in Wild World. After buying something, Redd will give the player an invitation to send to other players - If they visit Redd's, he would give 1,000 Bells to the player. The entry fee is 3,000 Bells.
He appears to have no connection with Lyle, who now runs the Happy Room HQ in the city. Therefore insurance does not exist and any forgeries cannot be refunded at all. To tell whether a painting is fake or not, talk to your villagers. If one of them complains about buying a forged painting from Redd, that means that the painting currently on display is a forgery.
In New Leaf, Redd visits the town on one random day of the week, setting up his tent in the plaza. Unlike the previous games, Redd no longer requires the player to do anything in order to enter his tent, and his furniture is limited to art. Within his tent, Redd sets up four works of art on display. If purchased, the item will arrive by mail the next morning. Each player can only purchase one work of art, and once that work of art is selected, the player cannot change that selection.
Like before, Redd's items often include forgeries among them, although at least one item is guaranteed to be genuine. Attempting to sell a forgery will result in the shopkeeper identifying the work of art as fake, and the player will be asked to pay a disposal fee to get rid of it. If the player chooses otherwise, the forgery can also be disposed by using a furniture or public work capable of item disposal.
Unlike previous games, however, identifying forgeries is made much easier. While the player is browsing the items in the tent, camera controls are enabled to allow the player to examine the artworks more closely. While certain works of art are always genuine, forgeries have noticeable differences from their real counterparts.
For example, the Gallant Sculpture, based on Michelangelo's David, has a cloth on his left shoulder. The fake Gallant Sculpture has the same cloth on both shoulders instead.
 Other appearances
Redd can both be seen as a trophy, and as a spectator in Smashville.
 Names in other languages