Thievul

Thievul's main niche stems from its ability, Unburden, which, in combination with Nasty Plot, makes it a powerful Terrain sweeper that teams can struggle to revenge kill. On top of naturally exploiting defensive Ghost-types like Doublade and Jellicent, Thievul also has coverage for Steel-types and Gigalith, both of which tend to annoy other special attackers. Thievul can also use Choice Specs to become a dangerous wallbreaker that, with proper positioning, can force many switches and capitalize on them thanks to the 2x boost Stakeout gives. However, Thievul's Speed, while decent for an offensive Pokemon, often leaves it forced out by a myriad of faster threats like Archeops and Whimsicott. Its pure-Dark typing leaves it with little switch-in opportunities due to weaknesses to common Bug-, Fighting-, and Fairy-type moves, and its poor overall bulk gives it no favors. Thievul is also heavily reliant on prediction and boosts from either Nasty Plot or Stakeout to succeed, as its Special Attack is middling and Dark Pulse has mediocre Base Power. Finally, Thievul can be blanked by special walls such as Articuno and Aromatisse, which take little from all of Thievul's common moves.