Moves
Recover allows Sableye to stick around throughout the match, advancing to the top of the priority bracket and reliably healing half of Sableye's total HP. Will-O-Wisp helps Sableye handle most physically offensive Pokemon better, as a burn is capable of shutting down a plethora of physical threats. The move is also great for racking up chip damage against bulkier threats, potentially wearing them down for a teammate. Taunt is lethal against defensive Pokemon, simply preventing any attempts at setting up entry hazards, clearing hazards with Defog, statusing Sableye, healing, or Taunting Sableye before it can heal itself. Knock Off, although doing pitiful damage to most Pokemon, removes the target's item and limits its staying power or offensive presence, making opposing threats easier to wear down. Snarl is used on teams that have an harder time handling strong specially oriented wallbreakers, namely Hydreigon, allowing Sableye to tank repeated hits a lot more easily or allow a teammate to switch in with more ease. Foul Play is also worth considering, since it allows Sableye to damage physically offensive Pokemon a lot harder, most notably Mega Absol, which is free to use Sableye as setup fodder otherwise. However, against defensive teams and most special attackers, it is the inferior choice.
Set Details
The entire set revolves around Sableye's ability, Prankster, as the boost in priority to Sableye's status moves encompasses its viability; its ability to heal or cripple threats before they can make a move gives Sableye a rather unique niche in UnderUsed. The given EV spread is biased in favor of Special Defense in order to help Sableye manage threats such as Mega Blastoise and Choice Scarf Hydreigon. Will-O-Wisp mitigates the need for investment in its Defense stat in most cases: only Fire-types, Pokemon with the Guts ability, and Mega Absol are unperturbed by Will-O-Wisp, and they will beat Sableye one-on-one in most cases regardless. However, an alternate spread of 252 HP / 252 Def / 4 SpD with an Impish or Bold nature can be used if Sableye's team absolutely needs the extra defensive support and is capable of comfortably taking on a wide range of special attackers.
Usage Tips
Without Snarl, Sableye is typically incapable of handing powerful special attackers, such as Choice Specs Hydreigon, Nasty Plot Infernape, and Mega Sceptile, and should not be left in on such threats. However, even with Snarl, Sableye will have a hard time dealing with them. Status conditions will limit Sableye's effectiveness, so it must try to Taunt any status users before receiving a Toxic or Will-O-Wisp. Scald users should be avoided by Sableye, as it cannot prevent stray burns from landing. Instead, bring Sableye in on Pokemon with low offensive capacities, like Froslass, Blissey, and Cresselia, and start disrupting the opposing team from there. The certain few offensive Pokemon you can safely switch Sableye in on are those that can't do much back to it, like Toxicroak, Reuniclus, and Snorlax.
Team Options
Answers to powerful special attackers, such as Nasty Plot Infernape and Choice Specs Hydreigon, are a must, as both can easily switch in on Will-O-Wisp and begin demolishing Sableye with powerful STAB attacks. It's a tall order, but Pokemon like Cresselia can beat Nasty Plot Infernape, and Sylveon walls Hydreigon. Faster offensive teammates, like Tornadus and Mega Aerodactyl, will also remove both Infernape and Hydreigon with ease, but they cannot afford to switch into them. Entry hazard setters such as Forretress, Swampert, and Froslass benefit from Sableye's ability to block both Rapid Spin and Defog. The hazards such Pokemon set give Sableye an easier time pressuring the opposing team, as it forces a lot of switches and will be able to rack up additional chip damage. Pokemon that can tank hits from the Fire- and Fairy-type Pokemon that constantly threaten Sableye on the battlefield are naturally good partners for it. Empoleon can switch in for free on Sylveon and Florges and proceed to lay down Stealth Rock, while Suicune is easily one of the best blanket checks to Fire-type Pokemon in the tier. Generally bulky Pokemon, such as Sylveon, Snorlax, Mega Aggron, and Gligar, make for excellent teammates, as Sableye's naturally low defensive stats and inability to cripple a select group of attackers still leave it liable to powerful attacks. Cleric support from Sylveon or Blissey will allow Sableye to be played more recklessly, as it won't need to fear status as much. For more offensively oriented teams, Pokemon that benefit from Sableye's ability to disrupt and wear down teams with Will-O-Wisp and Knock Off are great partners. Good examples of such Pokemon include Mega Sharpedo, Mega Swampert, Lucario, and Tornadus. Keep in mind that Pokemon like these really thrive on Spikes-stacking teams and Sableye alone is not enough to let them thrive.