Zoroark would be an interesting case in RU. It sits at a nice speed tier of 105 which, while outsped by the top tier of speed threats is still quite good and beats most things. Zoroark's best set would probably be a Choice Specs set, luring in Physical walls and crushing them with Specs boosted Dark Pulse/Flamethrower/Focus Blast. It could form effective combinations with Pokemon like Scolipede and especially Hitmonlee and co. being able to lure in Psychic attacks which Zoroark is immune to. Notably in the latter case, a Hitmonlee disguised Zoroark will be able to lure in and destroy Uxie, Misdreavus, Golurk, Rotom, Dusknoir and Spiritomb to an extent, opening up paths for a Hitmonless sweep. Other options for Zoroark include a Nasty Plot set, a Swords Dance set, a Choice Scarf set and a Mixed attacker set. The last set, a mixed attacker would likely be Zoroark's next best set, with Dark Pulse, Low Kick, Flamethrower and Sucker Punch. Low Kick allows Zoroark to hit Pokemon such as Clefable and (lol) Munchlax more effectively than its other options, while the other attacks give Zoroark a good mix of power, coverage with a last ditch priority attack as well. Nasty Plot is a nice option for Zoroark, as it can use it Illusion to create a set up opportunity for it to go to work with its Dark / Fighting / Fire coverage as very few Pokemon can take +2 attacks from Zoroark. Similarly a Swords Dance set with Night Slash / Low Kick / Sucker Punch can function similarly with the added bonus of priority for the faster Pokemon, though it unfortunately suffers from slightly greater coverage issues than the Nasty Plot set. Finally, a Choice Scarf set can be effective as a cleaner and to take out faster Pokemon that see the illusory mon as a free kill. That said, the relatively low base power of most of Zoroark's moves and lack of boosting item makes this a less desirable option. The ultimate downfall of Zoroark with all of its set is Zoroark's extreme frailty. Its horrific 60 / 60 / 60 bulk means that it completely relies on its Illusion to create set up opportunities as any attack will KO or cripple it. In the case of the boosting sets, opposing priority is supremely threatening, particularly Mach Punch from Hitmonlee or Hitmonchan. Zoroark's bulk also means it is forced to switch out the moment a faster Pokemon or Choice Scarfer threatens to outspeed and KO it. This means that Zoroark will be taking a lot of recoil damage between SR, potential Spikes, a possible Life Orb and the occasional Toxic Spikes. Its longevity drops dramatically each time it has to switch. In short, Zoroark in RU will be the definition of a glass cannon, capable of great power and its Illusion creating KO and set up opportunities, but at the cost of dying to nearly anything.