Moves
Refrigerate Hyper Voice is very strong and can penetrate Substitutes as well. Blizzard is the move of choice if Aurorus chooses Snow Warning, and it slightly outdamages Refrigerate Hyper Voice factoring in hail damage. Freeze-Dry smacks Water-types such Lanturn, Gorebyss, and Mantine, OHKOing the last, usually making it the safest move to lock into and throw out against bulkier cores. It also deters the likes of Samurott and Poliwrath from trying to switch into Aurorus and threaten it out. Earth Power allows Aurorus to OHKO Pyroar, Eviolite Combusken, and Klinklang, as well as 2HKO Assault Vest Magmortar and opposing Aurorus. Frost Breath allows Aurorus to break through Calm Mind users such as Mega Audino and Musharna. Psychic is an option to hit Hariyama, although that is the extent of its usefulness.
Set Details
Maximum Special Attack investment with a Modest nature maximizes Aurorus's damage output. Maximum Speed investment is used to outspeed as many Pokemon as possible, but a Timid nature should not be considered, as it doesn't allow Aurorus to outspeed anything relevant. The remaining EVs should not be placed into HP, as that would only allow Aurorus to switch into Stealth Rock three times. Choice Specs gives Aurorus tremendous power, boosting its wallbreaking potential; it also helps facilitate Aurorus's hit-and-run role, allowing Aurorus to deal as much damage as possible in one blow before being forced out.
If Aurorus's teammates are hindered by hail (primarily Synthesis or Moonlight users, weather sweepers, and Sturdy users), Refrigerate is the safer, no-drawback ability to use. If your team isn't too heavily affected by hail or benefits from hail's disruption against the opposing team, Snow Warning can be used.
Usage Tips
Due to Aurorus's low Speed and exploitable typing, it mainly functions as a hit-and-run Pokemon. It usually uses a combination of its resistances and decent bulk to switch into foes like Weezing, Scyther, Haunter, Xatu, Articuno, and Choice Specs Swellow. From there, Aurorus can usually just click its most powerful Ice-type attack to shred the opponent's team, unless there is a particularly bulky foe that warrants the use of its other attacks. Although Aurorus can punch sizable holes into teams at any stage in the game, it should usually be used early-game to maximize wallbreaking opportunities. While Aurorus doesn't require entry hazard control to function, keeping Stealth Rock off its side of the field is helpful to preserve Aurorus's health, as it switches in and out often. Snow Warning has additional utility, as it allows Aurorus to disrupt the recovery of Vileplume, Gourgeist, and Musharna and proceed to threaten them with its powerful Ice-type moves.
Team Options
Aurorus pairs excellently with Fighting-type Pokemon, such as Combusken and Primeape, as Aurorus can easily threaten the likes of Weezing, Gourgeist-Super, Vileplume, Musharna, Xatu, Swellow, and Pelipper and boasts the ability to switch in on most of them. In return, the Fighting-types do away with Steel- and Rock-types that may threaten Aurorus and help improve Aurorus's matchup against faster teams.
Fighting-types also happen to be Aurorus's greatest enemies, as they easily force it out; Pokemon such as Mesprit, Xatu, Weezing, Vileplume, Pelipper, and Musharna are examples of good teammates that can switch into said Fighting-types. VoltTurn support from the likes of Scyther, Primeape, Rotom, and Swellow is nice to get Aurorus into battle safely or against a favorable matchup.
While not necessary, Pokemon that can remove or prevent Stealth Rock can make for favorable teammates; in particular, Hitmonchan is yet another Fighting-type that benefits from Aurorus's wallbreaking, whereas Xatu and Pelipper cover many of Aurorus's weaknesses. Because Aurorus is slow and usually only threatens bulky Pokemon, fast attackers or setup sweepers are helpful to patch up Aurorus's weakness to faster teams. The likes of Tauros, Swellow, Scyther, Shiftry, and Lilligant fit the bill, with a few of them also covering some of Aurorus's weaknesses; in return all of them appreciate Aurorus's ability to pressure most of their checks. Aurorus also likes partners that can provide speed control, such as Thunder Wave Xatu, Stun Spore Vileplume, and Tailwind Swellow.
If running Snow Warning Aurorus, it is important to note which Pokemon can benefit or get hindered from Hail. Rotom-F becomes an interesting teammate, as it can switch into Ground-type moves and its sole Ice-type STAB move in Blizzard becomes perfectly accurate. For the latter reason, Aurorus's teammates may consider Blizzard over Ice Beam as coverage moves. Some teammates may adapt around hail, such as Magic Guard Kadabra and Clefairy, whereas Pokemon that rely on weather for recovery, such as Vileplume, Gourgeist-Super, and Musharna, may not be advisable as teammates at all.