* Great all-around stats combined with a pure Dark-typing make Arceus-Dark a very capable Pokemon in balanced and defensive teams.
* Arceus-Dark is a good user of Defog, since it's sheer bulk and Dark-type Judgment allow it to take on most of the common Stealth Rock users in the tier, while also threatening Gothitelle and Mega Gengar, an ability that no other support Arceus forme has.
* Resistances to Ghost and Dark with the additional Psychic immunity lets Arceus-Dark check a plethora of common threats, such as Yveltal, Ultra Necrozma and Mega Gengar.
* Dark has good neutral coverage, hitting notable threats in the tier such as Necrozma-DM and Giratina-O, and gives Arceus-Dark good offensive presence.
* Arceus-Dark suffers from the Fairy-type prevalence, since it's unable to do anything aside from Toxic to them and is beaten down easily.
* Fighting-types such as Mega Lucario, while not as common as Fairy-types, are a struggle for Arceus-Dark to overcome.
move 1: Judgment
move 2: Recover
move 3: Toxic
move 4: Defog / Stealth Rock
item: Dread Plate
nature: 252 HP / 160 Def / 96 Spe
* Judgment is Arceus-Dark's best STAB option, hitting all types and letting it check Ultra Necrozma, Lugia, and Giratina-O.
* Recover keeps Arceus-Dark alive throughout the game and allows it to check the Pokemon it is supposed to.
* Toxic cripples common switch-ins to Arceus-Dark, such as Ho-Oh, Primal Groudon, and Arceus-Fairy, and enables it to defeat Yveltal one-on-one.
* Defog provides entry hazard removal, and Arceus-Dark's sheer bulk and Dark-type Judgment make it an acceptable user of the move.
* Stealth Rock can be used alternatively for entry hazard support if the team already has entry hazard removal.
* Fire Blast can be used to net a possible OHKO on Mega Lucario, Mega Scizor and Ferrothorn while also heavily damaging other Steel-types such as Magearna and Celesteela on the switch-in.
* Will-O-Wisp can be used over Toxic to cripple Marshadow and Mega Lucario, however, lacking Toxic makes Arceus-Dark unable to punish other switch-ins properly, such as Primal Groudon, and Fairy-types.
* Dread Plate is required for a Dark-type Judgment and to use Arceus-Dark.
* A Timid nature with 96 Speed EVs enables Arceus-Dark to outspeed everything up to maximum base 100 Speed Pokemon, including notable threats such as Timid Yveltal, and Palkia.
* The HP EVs, in tandem with the Defense EVs, maximize Arceus-Dark's bulk, notably letting it avoid the OHKO from +1 Adamant Mega Salamence Double-Edge after Stealth Rock and the 2HKO from a Life Orb Yveltal Oblivion Wing.
* A spread of 252 HP / 56 Def / 192 Spe with a Timid nature should be used if running Fire Blast or Will-O-Wisp, as it lets Arceus-Dark outspeed Jolly Mega Lucario.
* A bulkier spread of 252 HP / 240 Def / 16 Spe with a Bold nature can be used to outspeed neutral-natured base 90 Speed Pokemon and significantly increase Arceus-Dark's physical bulk, allowing it to take a Close Combat from Mega Lucario and Marshadow and a +2 Precipice Blades from Primal Groudon.
* Arceus-Dark works best on defensive teams that have strong Primal Groudon checks and need a resist to Dark or a Ultra Necrozma switch-in.
* Arceus-Dark should be used as the primary switch-in to Yveltal, Ghost-types such as Giratina-O and Lunala, and finally, Necrozma-DM.
* If using Stealth Rock, Arceus-Dark is a solid lead for most matchups, especially to the likes of Yveltal and Necrozma-DM.
* As Arceus-Dark cannot check offensive Primal Groudon sets, it shouldn't be left as the primary Primal Groudon check.
* Try to avoid being hit by Toxic, since Arceus-Dark will be hindered down significantly, making walling much more difficult.
* Use Toxic on possible switch-ins like Arceus-Fairy and Ho-Oh.
* Primal Groudon provides a switch-in to Fairy-types and Primal Kyogre and Stealth Rock support, or if Arceus-Dark is using Stealth Rock, Primal Groudon is freed to run a offensive set.
* Ho-Oh immensely benefits from Defog support, and handles Fairy- and Fighting-types for Arceus-Dark and Primal Groudon to an extent.
* Marshadow likes Arceus-Dark taking on Yveltal, and in return takes on threats such as Mega Lucario and Tyranitar, also giving an additional Necrozma check.
* Mega Gengar traps and eliminates Fairy-types and provides a Fighting-type immunity.
* Checks to offensive Primal Groudon sets such as Giratina-O, Lugia, Zygarde (to an extent) are recommended.
* Bulky Steel-types such as specially defensive Necrozma-DM, Ferrothorn, Bronzong, Magearna, and Mega Scizor are helpful for Arceus-Dark to deal with Fairy-types.
* A Perish Trap set consisting of Whirlpool + Perish Song allows Arceus-Dark to function as a good stallbreaker capable of trapping most defensive Pokemon, however, it is quite ineffective against more offensive teams.
* A Calm Mind+Refresh set can be a decent late-game sweeper against defensive teams, but this set is completely stopped by Fairy-types.
* Ice Beam can be used to check Rayquaza, Zygarde, and Mega Salamence.
Checks and Counters
**Fairy-types**: Most Fairy-types, such as Xerneas, Arceus-Fairy, and Magearna wall Arceus-Dark and KO it with their Fairy-type STABs. Xerneas and Arceus-Fairy have to be wary of Toxic, while Magearna shuts Arceus-Dark completely down and is only 3HKOed by Fire Blast.
**Fighting-types**: Mega Lucario, Marshadow, Blaziken, and Pheromosa can easily take down Arceus-Dark with their STAB Fighting-type attacks. However, due to their frailty they should avoid switching in on Judgment multiple, and have to watch out for variants carrying Will-O-Wisp or Thunder Wave.
**Certain Steel-types**: Bulky Steel-types that aren't weak to Judgment, such as Ferrothorn, Celesteela, and Mega Scizor, are immune to Toxic and can punish Arceus-Dark. However, they have to watch out for certain sets carrying Fire Blast.
**Blissey and Chansey**: Blissey and Chansey can shrug off any attack from Arceus-Dark with ease, remove status with Heal Bell or Natural Cure, and cripple Arceus-Dark with Toxic.
**Primal Kyogre**: Defensive sets of Primal Kyogre can wear down Arceus-Dark with the combination of Scald and Toxic, and remove status with Rest. Offensive variants with Calm Mind dislike being hit by Toxic, but threaten to OHKO Arceus-Dark with an +1 Origin Pulse.
**Ho-Oh**: Ho-Oh, with its massive special bulk, easily takes a Judgment from Arceus-Dark and can retaliate with a powerful Sacred Fire or Brave Bird, or simply Toxic it. However, Ho-Oh heavily dislikes being hit by Toxic, and is threatened to be 2HKOed by Judgment if it switches on Stealth Rock.