Resistance

The Resistance is a cadre of vigilantes centered in Telma's Bar of Castle Town. They are covertly working to restore peace in Hyrule in Twilight Princess. The Resistance includes Telma, Auru, Ashei and Shad. Rusl has also been a member for some time, who decided to seek them out after recovering from the attack on Ordon Village.

History
The Resistance is first introduced in the game when Telma in Kakariko Village compliments Link's skills and asks if he's thinking of putting them to use for Hyrule. She then reveals that she's a part of a group trying to do their part to protect Hyrule and invites the young hero to join them some time at her bar.

When Link enters the bar after taking Telma to Kakariko Village, the Resistance will be inside, but will treat him harshly. Later, when Link has been cursed by Zant and must traverse the loft of the bar, they can be overheard talking about him and considering apologizing. When Link next meets them after he withdraws the Master Sword from the Sacred Grove, they will apologize to him for their behavior and properly introduce themselves. Each of the members, with the exception of Auru who is at Lake Hylia in this part of the game, will tell Link the part of Hyrule that they're currently investigating: Ashei is working to discover Snowpeak's mysteries,, Shad is researching about the sky beings known as the Oocca, and although Rusl does not specifically mention what he's researching, Link later finds out that he was investigating the Sacred Grove in the northern Faron Woods.

From this point, the members of the Resistance will be of crucial help to Link as they lead him to find the location of the Mirror of Twilight and its missing Mirror Shards. The Resistance first advises Link to visit Lake Hylia, which is where Auru is currently located. When the young hero reaches the lake, Auru will help him gain access to the Gerudo Desert and, to an extent, the Arbiter's Grounds, learning about the Mirror of Twilight in the process. Ashei later on helps the young hero track down the Yetis of Snowpeak, so that he may go to the next dungeon, Snowpeak Ruins, and obtain one of the Mirror Shards. Afterward, Rusl lends Link the Golden Cucco in the northern part of the Faron Woods in order for human Link to make it across the chasm that separates the Sacred Grove with Faron Woods, thus reaching the Temple of Time. Shad seeks out the secret of the Owl Statues around Hyrule, and indirectly leads Link to reactivating the Dominion Rod, as well as locating the Sky Cannon and thus ultimately reaching the City in the Sky, which is the location of the last Mirror Shard for the Mirror of Twilight. If at any point during his journey Link is unsure on where he should go next, he can always return to Telma's bar and speak to her, who will guide him as to which member of the group he should go visit in which part of Hyrule.

When Link enters Hyrule Castle, the Resistance assists him by saving him from a near death experience. Just as Link is about to get attacked by numerous enemies, the Resistance makes their entrance and defeat all of the enemies for the young hero, allowing him to proceed to the last few floors of Hyrule Castle and eventually reach Ganondorf.

After Hyrule returns to peace, Ashei, Shad and Auru will head off to the Sacred Grove to explore it, Telma will continue tending her bar and Rusl will return to the Ordon Village with his wife and children.

Trivia

 * Many of the characters here vaguely resemble the characters in the Lumpy Pumpkin from Skyward Sword. Shad resembles Keet, Auru resembles Rusta, Ashei resembles Kina and Telma resembles Pumm.
 * The name "the Resistance" remains fairly little-known as it was not used in-game or in any official material except the Twilight Princess trading cards, as well as Hyrule Historia several years later. As such, the Resistance was frequently known by fan-made monikers such as the or simply "the Group."