With Eviolite, Dragonair is a very bulky and dangerous setup sweeper that can come in either mid-game to wallbreak or late-game to sweep the opponent. Dragonair easily sets up on weak defensive Pokemon and Pokemon often found in Fire / Water / Grass cores, even if they have Ice Beam, such as Lanturn, Slowking, Qwilfish, Uxie, Rotom-C, Roselia, Magmortar, Typhlosion, Sceptile, and Clefable, as well as some offensive Pokemon like Galvantula, Manectric, Lilligant, and Mesprit. Thanks to RestTalk (which lets it absorb sleep from the likes of Lilligant and Amoonguss) keeping it healthy and Marvel Scale boosting its Defense, Dragonair actually benefits from status and is meant to set up while it's afflicted with status. Dragonair can even sweep an entire team while it simply cycles between Rest and Sleep Talk, and sometimes it's even advantageous to do so thanks to the protection from priority Marvel Scale provides and the fact that Sleep Talk bypasses Sucker Punch. However, it's usually best to save Dragonair for mid- to late-game to begin a sweep. Outrage is the sole attacking move on the set, as Dragon is a very good attacking type in RU, and it's easy enough to eliminate the Steel-types from an opponent's team with Magneton support. Caution should be taken with using Outrage all willy-nilly though, and it should only really be used when the sweep is secured, otherwise confusion could cut Dragonair's sweep short.
A specially defensive EV spread takes advantage of both Dragonair's typing and the fact that Marvel Scale will often be boosting its Defense anyway. Marvel Scale is what makes this set work as well as it does, since the boosted Defense lets Dragonair set up on physical attackers it normally wouldn't be able to such as Spiritomb, Hitmonchan, defensive Crustle, and Entei. However, Shed Skin is still viable and can be used to increase the speed with which Dragonair can set up and sweep. If used, Sleep Talk should be replaced with Waterfall or Extreme Speed. Shed Skin is more recommended for more offensive sets, though.
Magneton support is highly, highly recommended to make this set work. Choice Specs Magneton in particular works phenomenally well to remove the Steel-types from the opponent's team. With the Steel-types gone, particularly the defensive brutes like Steelix, Aggron, and Escavalier, Dragonair has a much easier time sweeping with Outrage. Specs Magneton also has the power to weaken or eliminate other physically defensive walls like Tangrowth, Alomomola, and Poliwrath. Entry hazard support is also extremely helpful in Dragonair's case, as it lowers the amount of times it needs to set up with Dragon Dance to secure a sweep and also pushes some opponents into KO range of Magneton's attacks. However, if the setup opportunity arises, Dragonair can take the time to set up to +6, so entry hazard support isn't mandatory for it to work.
Another Dragon-type teammate to ensure Steel-types are out of the way, like Druddigon or Fraxure, is also recommended and can put a ton of offensive pressure on the opponent. Dragon Dance Fraxure works particularly well if Dragonair is used mid-game. Really strong physical attackers like Tauros, Hitmonlee, Medicham, Druddigon, Swords Dance Absol, and Kabutops can pose a threat to Dragonair, especially if it's sleeping and Sleep Talk doesn't select the right move for it. These kinds of threats need to be removed or a setup opportunity for Dragonair needs to be created before they can come in to ensure it can outspeed them. Ghost-types like Rotom can help with the Normal- and Fighting-types, and Steel-types like Magneton work well to weaken or remove Druddigon, Absol, and Kabutops. Finally, Dragonair is very prone to getting ruined by critical hits as it sets up, so a back-up plan is always needed. Knowing precisely when a good time to start sweeping is also needed to reduce the chance of this happening; should Dragonair be at +3, +4, +6? Damage calculations help in this endeavor.
