I asked your question here, where the user Hyperspace12 responded.
Is Spiritomb or Sableye better for Dark Monotype teams, and why? Thanks.
neither would be used for their dark immunity, as all the prominent fighting spammers(mons like keld urshifu gapdos etc) nuke both with their other stab, so mandibuzz almost always does the job better and more consistently with its superior bulk and access to moves like u-turn and defog. As for which is better, sableye definitely sees more use as dark's only out against iron defense kommo-o, whereas spiritomb has no niche at all.
Additionally, Sableye gets Prankster, a great asset. It's able to fire off priority Toxic, Will-O-Wisp, Recover, and Taunt, while Spiritomb is just slow, no other way to put it. It also gets Knock Off.
Hope I helped!