Red (also referred to as Rogue, or the Rogue) is character controlled by the player and the widow of @, the original rogue (presumably from the game of the same title). Accompanying her is a skeletal minion, and together they are able to surmount the majority of the dungeon's inhabitants. For stats, see the Races page.
Minor spoiler warning! The following section contains minor spoilers. You may want to refrain from reading it.
As mentioned before, Red is the widow of @. Her goal is to find the Amulet of Yendor to resurrect him, which happens to be held by his murderer, the Balrog. Red's thoughts can be read when she dreams, and she mentions that she was once a princess. She possesses a Handbag of Holding (a reference to the Bag of Holding in the original roguelike games) which can hold any number of weapons, pieces of armor, runes, and hearts, although it can only hold one key. She also has a Rune of Time, which activates to send her back in time to the beginning of the dungeons. Since the dungeons run in a chaotic time, all the items she has stored in the Overworld remain intact.