Slifer Red (Osiris Red in the Japanese version) is the lowest-ranked of the three dorms at Duel Academy. The reason why Slifer Red is ranked as the lowest of the dorms traces back to Seto Kaiba’s defeat by Yugi Mutou’s Slifer the Sky Dragon during the Battle City arc.
The head of the Slifer Red Dorm, in the anime, was previously Professor Lyman Banner. After Banner (as Amnael, the 7th Shadow Rider) lost a duel to Jaden Yuki, his body was destroyed but his cat, Pharaoh, caught Banner's spirit in his mouth to stop him from leaving. Currently, the Slifer Dorm is literally run by a cat. In the manga, the head of the Slifer Red Dorm is Midori Hibiki.
In the beginning of the anime, Dr. Crowler expressed a great dislike for the students in this dorm, going as far as to set up stakeouts and rigging duels to find any opportunity to expel Slifer students. The students in Obelisk Blue shared his dislike, and usually exploited the Slifers' low ranks by calling them names such as "Slifer Slacker", "Slifer Slime", or "Slifer Scum" (in the Japanese version, they were commonly called "dropout boys"). However, as time continued, students from all dorms began flocking to Slifer Red. Examples include Alexis Rhodes, Tyranno Kenzan, Syrus Truesdale and Blair Flannigan.
However, by the end of the series, the only student officially enrolled in Slifer Red appears to be Jaden Yuki.
The Slifer Red Students students wear a jacket that usually extends to the waist. The Jacket has a band which matches the color of the jacket at the cuffs of the arms. The jacket also has a white band around the shoulders that has a snap, or button to keep the jacket closed, and another band which also matches the color of the jacket wraps around the bottom of the jacket which also serves the purpose of keeping the jacket closed. (although Jaden Yuki keeps it open)There is a white decorative shape, with a darker red border on the chest of the jacket.
Some second-year (or higher) Slifer Red Students (like Chumley Huffington) wear a different colored jacket, a version whose main color is white instead of red. Just like the previous jacket it usually extends to the waist. The jacket has a band which matches the color of the jacket at the cuffs of the arms. The jacket also has a red band around the shoulders that has a snap or button to keep the jacket closed, and another red band that wraps around the bottom of the jacket to keep the jacket closed. There is a decorative shape, with a darker red border on the chest of the jacket.