Revenankh was a Pokemon made to be the perfect Bulk Up user, and while it might have taken a hit in viability due to the addition of the Fairy type, it is still one of the best users of the move. Revenankh's excellent Ghost / Fighting STAB combination allows it to hit the entire metagame for at least neutral damage, allowing it to forgo coverage moves. Revenankh's decent base 105 Attack isn't the most ground-shaking, but it is more than enough for a Bulk Up user. It also has great natural bulk of 90 /90 /110, and that in combination with reliable recovery and STAB Drain Punch allows Revenankh to tank most neutral hits, greatly contributing to its ability to set up. Revenankh also has a fantastic ability in Shed Skin, which allows it to shrug off damaging status such as poison or burn, and reliably set up in the face of Scald. Ghost / Fighting is a decent defensive typing, as it gives Revenankh an immunity to Normal- and Fighting-type moves and neutrality to Knock Off, which makes it one of the few Pokemon able to spinblock Colossoil reliably.
While Revenankh is a phenomenal Bulk Up user, its low Speed and average starting Attack stat mean its Bulk Up set is by far its best set, and as a result, it is predictable. Shadow Sneak is necessary for it to strike first, and without several boosts under its belt, it can be underwhelming. Revenankh's typing also leaves it weak to Fairy- and Flying-type moves, two types that are very common in the metagame, and its reliance on Bulk Up to deal damage leaves it walled by Unaware users, most notably Clefable.
Bulk Up will allow Revenankh to set up on physical attackers, and after several boosts it can deal heavy damage to most Pokemon. Drain Punch is Revenankh's best Fighting-type STAB move, as it has decent Base Power and helps prolong Revenankh's longevity by recovering HP. Shadow Sneak is the recommended secondary STAB attack, as it achieves perfect neutral coverage with Drain Punch and is necessary to hit faster threats first. It can be used to get that last bit of damage on a sweeper such as Aurumoth, but it won't be doing any major damage without a couple boosts. The last moveslot is used either for healing or additional coverage; reliable recovery helps with setting up, whereas additional coverage lets Revenankh get past its would-be checks reliably. Moonlight is preferred, as it provides Revenankh with a reliable source of recovery, but Rest can also be used, as it has more PP and heals more HP. The two potential turns lost can leave Revenankh susceptible to being worn down by powerful attackers, but Shed Skin can help mitigate this. Earthquake is also an option, as it allows Revenankh to beat Mollux and Plasmanta, which can otherwise be difficult for Revenankh to beat. Ice Punch allows Revenankh to beat Tomohawk lacking Taunt or Haze, as well as deal heavy damage to Mega Altaria.
The given EVs and nature give Revenankh the highest possible special bulk, because Revenankh can boost its Defense by itself. The spread also allows Revenankh to act as a reliable check to special attackers such as Syclant and Levitate Stratagem, especially when running a recovery move to heal off the damage it'll take in the process. Leftovers gives Revenankh passive recovery and is very important for sets running a third attack. Shed Skin is the best ability for this set, as it allows Revenankh to shrug off status with a little luck, letting Revenankh set up in the face of Toxic and Scald users. This is especially helpful versus passive walls, such as Chansey, and also allows Revenankh to sometimes wake up early from Rest sleep.
Revenankh does not have the stats to deal heavy hits without boosting, so try to boost up as much as possible without leaving Revenankh vulnerable to being knocked out. Revenankh is fully capable of 2HKOing or OHKOing Pokemon after several boosts. The boosts are also vital in preventing Revenankh from being revenge killed by physical attackers. As Revenankh's main use is as a win condition, it is vital that you weaken or KO the foes that can stop it, mainly Fairy-types, Tomohawk, and phazers, or else any attempt at sweeping will be stopped short. The ideal Pokemon for Revenankh to set up on are either passive walls, such as Chansey, or physical attackers that cannot hit it super effectively or boost up alongside it, such as Landorus-T, Mega Sharpedo, and Mega Beedrill.
Stealth Rock support is much-appreciated, as it helps wear down the Flying-types that can check Revenankh. Pyroak can set up Stealth Rock and is able to beat or at least wall most Fairy-types, and while they do stack a Flying weakness, Revenankh can reliably check some Stratagem and other Rock-types that threaten Pyroak. Steel-types also make for good teammates, as they are generally able to take the Fairy- and Flying-type attacks aimed at Revenankh, and in return Revenankh can take the Fighting-type attacks aimed at them. Heatran, Ferrothorn, and Scizor all make for notable teammates, as the first two can reliably set up Stealth Rock while all three can punish Fairy-types. Pokemon that can reliably remove Tomohawk are essential, as it can put a hard stop to Revenankh, so Gothitelle and Fairy-types make good for teammates. Clefable in particular can set up Stealth Rock and beat opposing setup sweepers by virtue of Unaware. Pokemon that can handle Flying-type spam, such as Cyclohm, Skarmory, and Plasmanta, make for good partners as well, especially because Cawmodore and Talonflame can use Revenankh as setup bait if it is lacks a Bulk Up boost. Colossoil, along with other Dark-types, can be used to help alleviate Revenankh's Psychic weakness, but they stack a Fairy-type weakness and Revenankh can beat most Psychic-types itself after several boosts.
Shadow Punch or Hammer Arm can be used for their higher Base Power but are generally inferior to Drain Punch and Shadow Sneak as they lack both recovery and priority. Knock Off, Power Whip, or Rock Slide can be run as a third attack option in the last move slot, but none of them add anything noticeable to Revenankh's already good neutral coverage. Knock Off has redundant coverage with Shadow Sneak, but it can remove items such as Eviolite and Leftovers. It's worth noting that the biggest user of Eviolite, Chansey, and the biggest user of Assault Vest, Colossoil, are already hit super effectively by Revenank's Fighting-type STAB move. Power Whip's main niche is that it can hit Mega Slowbro and Quagsire harder then anything else, but aside from those two, it hits nothing else noticeable. Rock Slide can be used to hit Flying-types, such as Mega Charizard Y and Talonflame, hard. Taunt or Glare can be used in the last moveslot as well, but does not offer much in terms of supporting Bulk Up. Taunt can be used to better set up on walls or to prevent phazing, but considering that it requires either dropping a STAB move or recovery, it is a niche option. Glare can be useful for shoring up Revenankh's poor Speed and crippling switch-ins, but has no use aside from that. Toxic can be run in the last slot to cripple some switch-ins but it has no use otherwise. A physically defensive spread of 252 HP / 4 Atk / 252 Def can be used to allow Revenankh to switch into Colossoil with impunity, but this is only ever necessary on teams that need a reliable spinblocker to Colossoil, namely Sticky Web teams. A Choice Band set can be used, as it allows Revenankh to hit hard without the need for boosts, but this set leaves Revenankh locked into moves and is in generally a niche option. Its biggest selling point is Trick, which can be used to cripple most physical walls, such as Tomohawk, Cyclohm, and Pyroak.
Checks and Counters
Unaware: Unaware users, the most prominent being Clefable, are the most reliable checks to Revenankh. Quagsire and Arghonaut fear nothing short of Power Whip from Revenankh, and Clefable can hard counter Revenankh completely.
Fairy-types: Fairy-types are almost impossible for Revenankh to beat, as most, such as Mega Altaria, Mega Diancie, and Sylveon, can take a +6 Shadow Sneak and either KO or deal heavy damage to Revenankh. Mega Gardevoir can tank a +2 Shadow Sneak from full health and OHKO Revenankh with Hyper Voice, but it will take a large amount of damage in the process. Clefable can completely counter Revenankh by virtue of its good bulk and Unaware.
Flying-types: Flying-types such as Mega Pinsir and Talonflame can threaten Revenankh out with their powerful STAB moves, and Revenankh requires many Bulk Up boosts on to even consider beating them. Tomohawk can completely counter Revenankh if it runs Haze, negating any Bulk Up boosts Revenankh had accumulated. Even if Tomohawk lacks Haze, Revenankh will need to boost many times to beat it, and because Air Slash is a clean 3HKO, Revenankh will be under heavy pressure to do so. Offensive Tomohawk sets will also cleanly OHKO Revenankh with a Life Orb-boosted Hurricane.
Mega Sableye: Due to its Dark / Ghost typing, Mega Sableye can only be hit by Shadow Sneak or a coverage move, and it can use Taunt to prevent Revenankh from boosting or healing. Metal Burst variants can severely limit Revenankh. Calm Mind sets can also set up and hit Revenankh hard with Shadow Ball.
Stat Boost Removal: Haze and Clear Smog can completely reset Revenankh's boosts, preventing it from sweeping and taking away most of the pressure it can put on a team. The most effective users would be Tomohawk and Quagsire, which can already wall Revenankh. Amoonguss can also stop Revenakh variants that don't run a third attacking move, as can Plasmanta.
Phazing: Phazing moves can stop a Revenankh sweep short, and Pokemon with high Defense, such as Skarmory, Cyclohm, and Pyroak, can reliably use them, although they will have take heavy damage from a fully boosted Revenankh, and they fail outright if Revenankh carries Taunt.
Powerful Special Attackers: Pokemon that can take a Shadow Sneak and hit hard, such as Mega Charizard Y, Tornadus-T, and Mega Pidgeot, will be able to severely damage Revenankh with super effective or powerful STAB attacks, but they must be wary of Revenankh when it has accumulated multiple boosts.