Overview
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Dialga's typing, bulk, and power allow it to remain a threat in ORAS Ubers; it is also capable of setting and keeping up Stealth Rock with ease due to its expansive movepool, which allows Dialga to deal with the common Defog and Magic Bounce users in the tier. The newcomer Primal Groudon does hurt Dialga's viability, however, as it can also fulfill the same role of a Stealth Rock setter as Dialga can and, because it comes with more perks, outclass Dialga in some areas. Dialga's Ground-type weakness hurts its viability even more in a metagame dominated by Primal Groudon, and Dialga's lack of reliable recovery means it can be very susceptible to being worn down.
Support
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name: Support
move 1: Stealth Rock
move 2: Draco Meteor
move 3: Fire Blast / Flash Cannon
move 4: Toxic / Roar
ability: Pressure
item: Shuca Berry / Leftovers
evs: 244 HP / 252 SpD / 12 Spe
nature: Calm
Moves
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Stealth Rock is a key niche that Dialga can provide to a team and is what this set is built around. Draco Meteor provides a great STAB attack for Dialga, OHKOing nearly everything weak to it with the exception of Latias or and Giratina while also dealing great damage to neutral targets, making it very difficult to switch into when taking its Dialga's possible coverage into consideration. Fire Blast hits the majority of Pokemon that resist Dragon in the tier for great damage, OHKOing Pokemon such as Mega Scizor, Ferrothorn, and Genesect. Flash Cannon is an alternative coverage move that can be used to take out Mega Diancie, Rock Arceus, and Tyranitar if needed. Toxic can pressure bulky Defog Arceus formes and prevent them from removing Stealth Rock while also catching Dialga switch-ins such as Ho-Oh and Lugia. Roar can also be used in place of Toxic to phaze potential setup sweepers that may try to set up on Dialga after it has used Draco Meteor, and Roar can help to prevent it from being trapped by Shadow Tag users. Rest could also be used in the last slot, as a common way of beating Dialga is through residual damage and Rest can stop that from becoming an issue.
Set Details
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Using 244 HP EVs and maximum Special Defense while using with a Calm nature allow Dialga to take on the numerous special attackers of the tier, such as Mewtwo, Kyogre, and Palkia. The 12 Speed EVs are used to let Dialga outspeed maximum Speed Diancie before it Mega Evolves. Shuca Berry allows Dialga to become a great check to Mega Salamence, and it can prevent Primal Groudon from easily taking advantage of Dialga's Ground weakness. Leftovers can also be used if the passive recovery is necessary. A physically defensive spread could also be used instead to check Pokemon such as Rayquaza, Zekrom, and Mega Salamence better.
Usage Tips
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Dialga's typing alone can provide plenty of opportunities to switch in and set up Stealth Rock, and can do so multiple times in a match. However, Dialga's lack of recovery without Leftovers means that some caution should be used when switching in repeatedly. Toxic possible Defog users such as a bulky Arceus and attack with Draco Meteor to pressure them while constantly setting up Stealth Rock to keep it on the field. Be wary of possible setup sweepers after using Draco Meteor; if they can deal with being poisoned, then you might find yourself in trouble. This isn't an issue if you are using running Roar, however.
Team Options
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This type of Dialga is based around supporting its teammates, and therefore it doesn't require much support of its own. Pokemon that appreciate Stealth Rock being on the field to aid in sweeping, (comma) such as Geomancy Xerneas and Extremekiller Arceus, (comma) make for great partners. Pokemon that have good defensive synergy with Dialga, (comma) such as Ho-Oh, Giratina-O, Latios, Latias, and Lugia, (comma) also pair well with this set; Latios, Latias, and Giratina-O in particular make for great teammates due to their Ground immunity. Note that if you are using Fire Blast over Flash Cannon, Mega Diancie can completely shut this set down, (comma) so be sure to have an answer to it, with possibilities being Ground Arceus or Primal Kyogre. Dialga generally finds its way onto teams that need a Stealth Rock setter that isn't Primal Groudon.
Offensive
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name: Offensive
move 1: Draco Meteor
move 2: Fire Blast
move 3: Flash Cannon
move 4: Stealth Rock / Thunder
ability: Pressure
item: Shuca Berry / Life Orb
evs: 244 HP / 252 SpA / 12 Spe
nature: Modest
Moves
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Draco Meteor from this Dialga variant will severely dent just about anything that doesn't resist it and makes it a terror to switch into. Having both Fire Blast and Flash Cannon means that Dialga now has excellent coverage across the entire tier, (comma) and with the Special Attack investment, the attacks will OHKO just about anything weak to them. Stealth Rock can still be set up reliably and works great on offensive teams that would otherwise not have a user of the move. Thunder is an alternative move that allows Dialga to hit Ho-Oh, Lugia, Primal Kyogre, and Water Arceus super effectively and works great if a Stealth Rock user is already on the team. Stone Edge is an option if using Life Orb, letting Dialga net a surprise OHKO on unsuspecting Ho-Oh.
Set Details
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The HP EVs give Dialga maximum bulk, while maximum Special Attack and a Modest nature give Dialga excellent damage power behind its attacks. 12 Speed EVs allow Dialga to outspeed Diancie before Mega Evolution. Shuca Berry is preferred to give Dialga the extra niche of being an offensive check to Mega Salamence and also lets it live survive an attack from Primal Groudon in a pinch. Adamant Orb is an alternative item option (redundant with alternative imo) that adds great power to Dialga's STAB attacks and can also bluff a different item what item Dialga is holding. Life Orb gives Dialga maximum wallbreaking power on all of its moves, notably letting Dialga OHKO Primal Groudon with Draco Meteor after Stealth Rock damage. Shuca Berry is generally preferred over either Orb for the utility it brings.
Usage Tips
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Use Dialga's great typing to provide switch-in find opportunities to switch in and set up Stealth Rock while using the tremendous power behind its attacks to ward off Defog or Magic Bounce users. This set does not have as much bulk as the support set and lacks recovery, so take care to avoid unnecessary damage. Keeping this Dialga variant healthy is key for offensive teams to be able to stop Mega Salamence. Flash Cannon can catch out unsuspecting Fairy-types and easily take them out. It should be noted that if Dialga cannot force its way past Defog users with recovery, it is unable to stop Defog and may kill momentum after using Draco Meteor.
Team Options
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This Dialga set best fits on offensive teams that require a Stealth Rock setter that can also check Mega Diancie and Mega Salamence due to the Shuca Berry. Teams that are using Pokemon that can clash with Primal Groudon, (comma) such as Ground Arceus, (comma) can use Dialga as an alternative Stealth Rock user. Checks to Primal Groudon make for great teammates, as Primal Groudon and Mega Salamence are commonly seen together, and Dialga cannot deal with both. Examples include Giratina-O, Latias, and Latios. The aforementioned Pokemon also help with Dialga's Fighting-type weakness, as they can switch into Mega Blaziken, Mega Lucario, and Mega Mewtwo X. Strong physical wallbreakers such as Primal Groudon and Mega Salamence can break past the specially bulky Pokemon that Dialga cannot do very well against, namely Ho-Oh. Mega Gengar can also potentially trap and remove possible Dialga checks.
Choice Scarf
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name: Choice Scarf
move 1: Draco Meteor / Dragon Pulse
move 2: Fire Blast
move 3: Flash Cannon
move 4: Thunder / Sleep Talk
ability: Pressure
item: Choice Scarf
evs: 4 HP / 252 SpA / 252 Spe
nature: Modest
Moves
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Draco Meteor provides the best STAB option for this set due to its power. Dragon Pulse is a more consistent alternative that doesn't have any drawbacks, but it is notably weaker in comparison. Fire Blast and Flash Cannon provide excellent coverage and widen the list of Pokemon that Dialga can potentially revenge kill. Thunder hits Primal Kyogre, Lugia, Ho-Oh, and Water Arceus, which could easily take the other attacks on this set. Sleep Talk gives Dialga added utility by letting it become becoming a sleep absorber that can potentially surprise Darkrai, but this can be very risky. Outrage can be used to hit Latios and Latias much harder and potentially revenge kill Calm Mind variants; (semicolon) — use a Rash nature if using running Outrage.
Set Details
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Maximum Special Attack and Speed EVs with a Modest nature give Dialga the tools to be an effective Choice Scarf user, hitting as hard as possible while being able to outspeed most of the tier barring the offensive Deoxys formes and Speed tying with other base 90 Speed scarfers Choice Scarf users such as Zekrom. A Timid nature can be used to allow Dialga to outspeed Deoxys-A and other potential Choice Scarf users such as Xerneas and Genesect, (comma) but its attacks become noticeably weaker.
Usage Tips
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Choice Scarf Dialga should mainly be used for revenge killing, and it has a cool ability to take down a weakened Extremekiller Arceus in a pinch thanks to Dialga's typing. This set will more than likely catch the enemy off-guard and can get some surprise KOs that may not have been possible without the Choice Scarf. This Dialga set can be fairly easily played around once the Choice Scarf is revealed, but it has the coverage to hit predicted switch-ins for solid damage.
Team Options
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Pokemon with Ground-type immunities, (comma) such as Latias, Latios, and Giratina-O, (comma) make for great partners to this set, as revenge killing a threat with Draco Meteor may end up with a Primal Groudon coming in for an easy setup. Strong physical attackers such as Primal Groudon, Ho-Oh, and Mega Salamence can help to break past the special walls that Dialga cannot easily bypass. Entry hazard support can be useful to punish the switches that this Dialga set will force and also keeps Ho-Oh at bay. Switch-ins to Xerneas and Fairy Arceus are much appreciated, with examples being Primal Groudon and Ho-Oh, (comma) as Dialga will be forced out after using Draco Meteor. Ho-Oh switch-ins such as Rock Arceus or and bulky Salamence can also help Dialga, as Ho-Oh can handle Dialga's attacks relatively easy with the exception of Thunder.
Other Options
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Dialga has a bunch of possible other options, but they tend to run into more issues than the standard sets. Choice Specs Dialga is a possible set due to its insane power but runs into problems due to its average Speed tier and, once the set is revealed, can be played around. Thunder Wave is an alternative status move that can mess with numerous Dialga switch-ins, but it generally doesn't help Dialga's role as a Stealth Rock setter very much. Earth Power is an alternative coverage option for offensive sets that can 2HKO any Primal Groudon after Stealth Rock and also 2HKO the rare Poison Arceus, but it doesn't do anything notable outside of that. Bulk Up with physical moves such as Iron Head and Outrage is a niche set that finds itself having trouble with Will-O-Wisp Arceus formes, Primal Groudon, and Ho-Oh, all of which are commonly seen in the metagame. Trick Room Dialga can work very well on dedicated teams due to having a great typing and coverage along with having a somewhat low Speed tier.
Checks & Counters
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**Ground Arceus**: While most Arceus formes can switch into or deal with Dialga, Ground Arceus is the best at it, being able to switch into any move and deal serious damage back. Dialga can Toxic on the switch or possibly take a hit with Shuca Berry to try taking out a weakened Ground Arceus.
**Primal Groudon**: The specially defensive variant can switch into support Dialga with relative ease and force it out or set Stealth Rock of its own. Life Orb Dialga can 2HKO with Draco Meteor on the switch, and regular Dialga sets carry Shuca Berry, (comma) so the matchup isn't exactly straightforward. Groudon's lack of recovery can also work in Dialga's favor.
**Ho-Oh**: Thanks to Regenerator, Ho-Oh can switch into most of Dialga's attacks, force it out, and recover off the damage just by switching. Offensive Dialga sets can carry Thunder, which will 2HKO Ho-Oh, (comma) but it can be hard to hit Ho-Oh with the move.
**Primal Kyogre**: Due to Primal Kyogre's new base 160 Special Defense, nearly all variants can deal with Dialga. Specially defensive Primal Kyogre can switch into Dialga with impunity and proceed to wear it down with Scald. Calm Mind variants can also switch in and boost in front of Dialga. Offensive variants of Dialga with Thunder can 2HKO Calm Mind Primal Kyogre variants but still can't 2HKO specially defensive variants without a Life Orb.
**Bulky Arceus Formes**: Nearly all Arceus formes can switch into a Dialga at least once, and those that don't care for about Toxic are even better answers. Dialga can attempt to pressure with Draco Meteor or Toxic, (comma) but if the Arceus has Calm Mind + Refresh, Dialga is helpless without Roar.
**Special Walls**: Lugia, Blissey, and Heatran can take Dialga's attacks really well, and Lugia and Blissey also have reliable recovery to help with this. None of these Pokemon can actually take down Dialga very easily, however; they have to chip away slowly.
**Fighting-types**: While they don't have the easiest time switching in, Mega Mewtwo X, Mega Blaziken, (comma) and Mega Lucario all outspeed Dialga and OHKO with their STAB moves. Fighting Arceus also outspeeds Dialga and will 2HKO with ease.
