I wrote this three months ago, almost three months prior to the Dark Void nerf being mentioned. At the time, Darkrai was thought to remain as an extremely relevant threat. That being said, Darkrai's viability has turned to almost zero, where you have Hypnosis being a more valid option than Dark Void due to the additional 10% in accuracy. So you're correct, but please don't correct a statement that was made prior to the knowledge of this nerf, especially when the nerf has been made quite apparent since.Dark void's accuracy is lowered to 50%, and I don't think anyone will ever use it again in AG.
I guess I'll just keep talking about AG because I have no better way to spend the next few hours.

Solgaleo | Steel/Psychic | 137/137/107/113/89/97 | Ability: Full Metal Body
Solgaleo is much more than a decent Xerneas check with recovery. Its utility may not seem to be quite substantial at first; however, under further inspection, it is evident that Solgaleo has more than just a few tricks. This is what I expect to see running around in AG.
Defensive Sets
Specially Defensive:
Solgaleo @ Leftovers
Ability: Full Metal Body
EVs: 248 HP / 8 Atk / 252 SpD
Careful Nature
- Sunsteel Strike
- Stone Edge
- Morning Sun
- Metal Burst / Thunder Wave / Toxic
Specially Defensive Set mainly for tanking two +2 Moonblasts from Xerneas, while having a high chance to live two +2 Focus Blasts. It also has the offensive capability of 2HKOing Xerneas, while OHKOing Ho-Oh. The 8 Atk EVs are actually required to gain the guaranteed OHKO on standard Ho-Oh EVs from this generation. Morning Sun allows it to recovery its health back so Xerneas can't whittle it down over time and then overwhelm it eventually. Metal Burst can be useful as +2 Focus Blast Xerneas is OHKO'd back when hit by it. It also allows Solgaleo to OHKO Kyogre back after being hit by Origin Pulse; however, it should be weary that the Kyogre may be slower. If one does opt for Metal Burst, running less IVs to be under 216 Speed may be a good idea. Thunder Wave allows for speed control when the only Pokémon outspeeding at half is Deoxys-Speed. Toxic allows Solgaleo to help take down some support/Calm Mind Arceus formes Solgaleo could otherwise not touch.
8 Atk Solgaleo Sunsteel Strike vs. 184 HP / 28 Def Xerneas: 288-342 (65.6 - 77.9%) -- guaranteed 2HKO
8 Atk Solgaleo Sunsteel Strike vs. 248 HP / 0 Def Arceus-Fairy: 242-288 (54.6 - 65%) -- guaranteed 2HKO
8 Atk Solgaleo Stone Edge vs. 248 HP / 0 Def Ho-Oh: 416-492 (100.2 - 118.5%) -- guaranteed OHKO
8 Atk Solgaleo Sunsteel Strike vs. 248 HP / 0 Def Clefable: 372-438 (94.6 - 111.4%) -- 62.5% chance to OHKO
8 Atk Solgaleo Sunsteel Strike vs. 0 HP / 0 Def Mega Diancie: 528-624 (219 - 258.9%) -- guaranteed OHKO
252+ SpA Fairy Aura Xerneas Moonblast vs. 248 HP / 252+ SpD Solgaleo: 89-105 (18.6 - 22%) -- possible 6HKO after Leftovers recovery
252+ SpA Xerneas Focus Blast vs. 248 HP / 252+ SpD Solgaleo: 113-133 (23.6 - 27.8%) -- possible 5HKO after Leftovers recovery
+2 252+ SpA Fairy Aura Xerneas Moonblast vs. 248 HP / 252+ SpD Solgaleo: 177-208 (37.1 - 43.6%) -- 99.8% chance to 3HKO after Leftovers recovery
+2 252+ SpA Xerneas Focus Blast vs. 248 HP / 252+ SpD Solgaleo: 225-265 (47.1 - 55.5%) -- 19.1% chance to 2HKO after Leftovers recovery
252+ SpA Primal Kyogre Origin Pulse vs. 248 HP / 252+ SpD Solgaleo in Heavy Rain: 295-348 (61.8 - 72.9%) -- guaranteed 2HKO after Leftovers recovery
Physically Defensive:
Solgaleo @ Leftovers
Ability: Full Metal Body
EVs: 248 HP / 8 Atk / 252 Def
Impish Nature
IVs: 16 Spe
- Metal Burst
- Sunsteel Strike
- Roar
- Morning Sun
This thing can live the majority of the metagame's attacks and OHKO back with Metal Burst.
252+ Atk Mega Rayquaza V-create vs. 248 HP / 252+ Def Solgaleo: 378-446 (79.2 - 93.5%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Primal Groudon Precipice Blades vs. 248 HP / 252+ Def Solgaleo: 378-446 (79.2 - 93.5%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Choice Band Ho-Oh Sacred Fire vs. 248 HP / 252+ Def Solgaleo: 372-438 (77.9 - 91.8%) -- guaranteed 2HKO after Leftovers recovery
+2 252+ SpA Xerneas Focus Blast vs. 248 HP / 0 SpD Solgaleo: 318-375 (66.6 - 78.6%) -- guaranteed 2HKO after Leftovers recovery
+2 252 Atk Life Orb Arceus Earthquake vs. 248 HP / 252+ Def Solgaleo: 367-434 (76.9 - 90.9%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Spooky Plate Arceus-Ghost Shadow Force vs. 248 HP / 252+ Def Solgaleo: 336-396 (70.4 - 83%) -- guaranteed 2HKO after Leftovers recovery
The issue is that with this set, after you Metal Burst you're usually left useless for the remainder of the match. Unless you can send it in on Fairy Arceus or something passive later on, you just wasted your Solgaleo taking out one Pokémon. This would also be quite useful in some scenarios, if the majority of Pokémon listed above didn't have access to boosting moves. The best thing Solgaleo can do then is phaze, which isn't quite the utility you'd hope for in this Pokémon.
Offensive Sets
Standard Offensive
Solgaleo @ Life Orb
Ability: Full Metal Body
EVs: 252 Atk / 56 SpD / 200 Spe
Adamant Nature
- Sunsteel Strike
- Flare Blitz
- Stone Edge / Rock Tomb
- Morning Sun / Wild Charge / Flame Charge
Standard offensive set allows Solgaleo to pick up OHKOs on Xerneas, Arceus-Fairy, Diancie-Mega and Ho-Oh with ease, while 2HKOing the remainder of the metagame. Solgaleo would love an extra moveslot; however, it can still achieve many things with the four moves listed here. Sunsteel Strike is the main STAB used here, and allows Solgaleo to hit through Lugia and Lunala's respective abilities. Flare Blitz allows Solgaleo to hit Ferrothorn, Skarmory and Bronzong for full, while providing more solid coverage as Steel has many resists. Stone Edge/Rock Tomb rounds out the coverage and allows Solgaleo to hit Ho-Oh or Yveltal on the switch-in. Rock Tomb OHKOs Ho-Oh and decreases Yveltal's speed to under Solgaleo's. 2x Rock Tomb does often OHKO offensive Yveltal sets, but one should be weary of Sucker Punch and the potential low roll. Morning Sun provides Solgaleo with the chance to live longer in the game as well as increased recovery against Groudon switch-ins. Wild Charge and Flame Charge are alternate options that enable Solgaleo to do random things like help with checking Choice Scarf Kyogre or Primal Kyogre depending on the option chosen. Speed is invested at 200 to outspeed 252 Spe Neutral Natured Base 90s.
252+ Atk Life Orb Solgaleo Sunsteel Strike vs. 184 HP / 28 Def Xerneas: 491-580 (111.8 - 132.1%) -- guaranteed OHKO
252+ Atk Life Orb Solgaleo Sunsteel Strike vs. 248 HP / 0 Def Arceus-Fairy: 416-491 (93.9 - 110.8%) -- 62.5% chance to OHKO
252+ Atk Life Orb Solgaleo Sunsteel Strike vs. 248 HP / 0 Def Clefable: 632-743 (160.8 - 189%) -- guaranteed OHKO
252+ Atk Life Orb Solgaleo Flare Blitz vs. 252 HP / 0 Def Ferrothorn: 619-728 (175.8 - 206.8%) -- guaranteed OHKO
252+ Atk Life Orb Solgaleo Flare Blitz vs. 252 HP / 252+ Def Skarmory: 221-263 (66.1 - 78.7%) -- guaranteed 2HKO after Leftovers recovery
252+ Atk Life Orb Solgaleo Flare Blitz vs. 252 HP / 0 Def Bronzong: 343-406 (101.4 - 120.1%) -- guaranteed OHKO
252+ Atk Life Orb Solgaleo Stone Edge vs. 248 HP / 0 Def Ho-Oh: 707-837 (170.3 - 201.6%) -- guaranteed OHKO
252+ Atk Life Orb Solgaleo Stone Edge vs. 132 HP / 0 Def Yveltal: 338-400 (79.3 - 93.8%) -- guaranteed 2HKO
252+ Atk Life Orb Solgaleo Sunsteel Strike vs. 252 HP / 120+ Def Lugia: 161-191 (38.7 - 45.9%) -- guaranteed 3HKO after Leftovers recovery (Lugia can only Whirlwind back)
252+ Atk Life Orb Solgaleo Sunsteel Strike vs. 4 HP / 0 Def Arceus: 208-246 (54.4 - 64.3%) -- guaranteed 2HKO
Choice Band
Solgaleo @ Choice Band
Ability: Full Metal Body
EVs: 252 Atk / 56 SpD / 200 Spe
Adamant Nature
- Sunsteel Strike
- Earthquake
- Flare Blitz
- Stone Edge / Wild Charge
Choice Band hits Solgaleo hits like a bus. Sunsteel Strike OHKOs every fairy in the game, and acts as Lion's main STAB. Thanks to Choice Band, Earthquake can now 2HKO Support Primal Groudon as well as deal with the abundance of Steel types in the metagame bar Skarmory, Ferrothorn and Bronzong. This is why Flare Blitz is listed as a third move as it allows Solgaleo to hit the majority of the metagame for huge damage when the added to the aforementioned moves. Things that remain untouched by the above coverage include Ho-Oh and Primal Kyogre. This is why Stone Edge and Wild Charge are listed as potential fourth moves. Stone Edge OHKOs Ho-Oh guaranteed and Wild Charge deals massive damage to Primal Kyogre. Both moves also allow Solgaleo to 2HKO Defensive Yveltal. The EVs are used to outspeed 252 Spe Neutral Natured Base 90s. Max Attack to ensure maximum damage output against opponents while remainder put in Special Defense so it can come in on Xerneas's attacks with ease.
Only including those from the previous calcs that didn't OHKO:
252+ Atk Choice Band Solgaleo Sunsteel Strike vs. 248 HP / 0 Def Arceus-Fairy: 480-566 (108.3 - 127.7%) -- guaranteed OHKO
252+ Atk Choice Band Solgaleo Flare Blitz vs. 252 HP / 252+ Def Skarmory: 256-302 (76.6 - 90.4%) -- guaranteed 2HKO
252+ Atk Choice Band Solgaleo Stone Edge vs. 132 HP / 0 Def Yveltal: 390-460 (91.5 - 107.9%) -- 50% chance to OHKO
252+ Atk Choice Band Solgaleo Sunsteel Strike vs. 252 HP / 120+ Def Lugia: 186-219 (44.7 - 52.6%) -- guaranteed 3HKO after Leftovers recovery
252+ Atk Choice Band Solgaleo Sunsteel Strike vs. 4 HP / 0 Def Arceus: 240-283 (62.8 - 74%) -- guaranteed 2HKO
As evident above, it doesn't pick up many more OHKOs/2HKOs; however, extra power will always be beneficial in some scenarios.
Choice Scarf
Solgaleo @ Choice Scarf
Ability: Full Metal Body
EVs: 252 Atk / 4 SpD / 252 Spe
Adamant Nature
- Sunsteel Strike
- Earthquake
- Stone Edge
- Flare Blitz
Choice Scarf can be used to outspeed many prevalent threats, while still dealing massive damage. By using maximum speed investment at a neutral nature, it can outspeed max speed Deoxys-Attack, and is only outsped by Deoxys-Speed, Pheromosa and Ninjask. Solgaleo should be weary of switching in on Knock Off, but otherwise it has a lot of fun playing against Deoxys-Attack. Especially if the potential playstyle of Tapu Lele + Deoxys-A spam becomes a thing, Scarf Solgaleo could be more of a potent threat than anticipated. This set is pretty self explanatory otherwise. Hits fast with nice offensive coverage.
Psych Up
Solgaleo @ Leftovers
Ability: Full Metal Body
EVs: 162 HP / 252 SpA / 96 Spe
Modest Nature
- Flash Cannon
- Psych Up
- Morning Sun
- Psyshock / Thunderbolt / Calm Mind / Roar
As people started to run Psych Up Poisonceus, this might potentially become a thing. Flash Cannon, Psych Up and Morning Sun are quite self explanatory. AKA set up on Geomancy Xerneas, and then kill it. Solgaleo has such bad 4MSS with this set. It would love to run more than one of the last moves listed. Psyshock allows Solgaleo to hit Special walls like Blissey, Chansey, Ho-Oh and Kyogre; Thunderbolt hits the latter two better but struggles with Blissey and Chansey; Calm Mind allows further setup before you take it out, potentially the best option here; Roar gets rid of Xerneas's boosts and allows Solgaleo to "steal" its boosts. For once Solgaleo can actually benefit from its ability, as Moonblast won't drop SpA and Focus Blast won't drop SpD. The EVs allow Solgaleo to outspeed standard Geomancy Xerneas.