Amaura can be revived in Ambrette Town from the Sail Fossil, obtainable in Glittering Cave.
Great defensive stats, good offensive stats, an ability that makes Return absolutely broken... and a slew of weaknesses. The relatively late evolution of the Amaura line is not a big penalisation in comparison, as an Eviolite Amaura is perfectly bulky and capable on its own; however, having not one, but two double weaknesses to types that are relatively common - Fighting and Steel - detracts from the enjoyment of having an Aurorus on the team. Although Aurorus is usually capable of tanking non-STAB super effective moves even of those two dreaded types, if its health is full, this will hardly save players from getting a scare upon seeing unexpected coverage, which Kalos players do occasionally come across. Aurorus is amazing if used well, but compared to the other fossil options, it needs its trainer to know exactly what they are doing; it may be great all the way until the end, but it is not a Pokémon for the faint of heart.
Gym #2 - Grant (Cyllage City, Rock-type): Amaura can 2HKO Grant's own Amaura with Bulldoze, but only if it already outspeeds; Rock Tomb will compensate for the Bulldoze-induced Speed drop, as well as doing more damage than Bulldoze in general. Amaura should not fight Tyrunt: even if, once again, it has the certainty of outspeeding it - which will be removed if the opposite Amaura's Rock Tomb hits even once - a full power Return boosted by Refrigerate is a guaranteed OHKO only with a nature beneficial to Attack, and a critical Rock Tomb from Tyrunt will off Amaura from full.
Korrina (Geosenge Town, Fighting-type): Power-Up Punch will strike Amaura for unsurmountable damage and provide Lucario some prime setup fodder. Do not use Amaura.
Rival (Tower of Mastery): Amaura can stand Meowstic's Psybeams well with the Eviolite attached, and can 2HKO back with Return if it is at full power. Absol can be 2HKOed by Return as well, but will deal considerable damage to Amaura with Bite; do not fight it unless Amaura's health is high, or heal up as needed otherwise. Braixen is the only easy starter; Quilladin and Frogadier both have super effective STAB moves and should be avoided.
Gym #3 - Korrina (Shalour City, Fighting-type): It goes without saying that Amaura has no business fighting in this gym, if it wants to stay alive.
Rival (Coumarine City): Since the moves are the exact same as the Tower of Mastery matchup, the strategy has not changed. Amaura can absorb hits from Meowstic and then hit back, and also defeat Absol with the help of some luck or healing; it can also take on Braixen, but should not attempt the other two starter Pokémon.
Gym #4 - Ramos (Coumarine City, Grass-type): Amaura can actually do fairly well here. Its Return will OHKO both Jumpluff and Weepinbell, though it should be careful when fighting the latter, as its Grass Knot can kill with a critical hit if Amaura's Special Defense is not great. If its nature favours Speed, this will not be a problem as Amaura will likely outspeed Weepinbell. Gogoat's Grass Knot is not a straight up OHKO, but comes very close to it and Return cannot damage it enough to even out the matchup; stay away from that one.
Aliana (Kalos Power Plant): This matchup is neither good nor bad. The Eviolite will help Amaura take little in the way of damage from Assurance, especially since Mightyena will outspeed, but repeated Swaggers will be annoying if it does not manage to hit with Return, and even after one Swagger, Return will not OHKO for certain. Use caution.
Gym #5 - Clemont (Lumiose City, Electric-type): While Return would score a clean OHKO against Emolga, its Speed and Volt Switch will take it out of the battlefield before Amaura or Aurorus can kill it. The switch will be to Magneton, which can OHKO the dinosaur easily with Mirror Shot; Aurorus might live a hit, depending on its stats, but a critical hit will kill regardless of everything else. Brave and reckless players can run Bulldoze on Aurorus' moveset, bet on Emolga switching to Magneton on the first turn, and use Bulldoze straight off the bat; if the strategy works out, Magneton will be too slow to outspeed Aurorus afterwards and the second Bulldoze will kill it. This is not doable as Amaura. Interestingly, Heliolisk is a viable opponent for both: Bulldoze + Return will KO Heliolisk regardless of evolutionary status, and Heliolisk's Grass Knot is a 2HKO as Aurorus, but a 3HKO as Amaura with the Eviolite attached. If you still have Amaura, watch out for Thunderbolt under the effects of Electric Terrain: it can kill from full health with a critical hit.
Rival (Route 14): Both Eviolite Amaura and Aurorus fare well in this matchup, scoring a clean 2HKO against Meowstic and Absol with Return. They can also take on Delphox with Rock Tomb or Ancient Power. Chesnaught and Greninja cannot be fought, as both have strong STAB moves to hit them with.
Gym #6 - Valerie (Laverre City, Fairy-type): Mawile may seem scary, but it actually has no Steel moves, so Aurorus can 2HKO it with Thunderbolt (which does more damage than Bulldoze). Mr. Mime's Psychic is a 3-4HKO depending on Aurorus' stats, and it can be 2HKOed with Return, with an OHKO possibility if one of Aurorus' teammates managed to set up entry hazards. Sylveon can also 3HKO at best, and Return will dispose of it just fine; Aurorus may need to heal once or twice if it must take on all of Valerie's Pokémon, though.
Celosia and Bryony (Poké Ball Factory, tag battle with rival): Neither Manectric nor Liepard pose a significant threat to Aurorus, and Return 2HKOs both of them. Dispose of Liepard first, as it can boost its Attack with Hone Claws.
Mable (Frost Cavern): Rock Tomb scores a certain 2HKO against Houndoom, whose best move is Foul Play and can only hope to 3HKO Aurorus.
Rival (Anistar City): Aurorus can 2HKO Meowstic and Absol with Return, and take on Flareon or Delphox with a Rock move of choice, preferably Rock Tomb. Freeze-Dry is a 2HKO on Greninja, but its Water Shuriken may do surprising amounts of damage; it is best to fight a better counter for this Pokémon. Vaporeon should not be fought by any means; it knows Muddy Water. Jolteon's Double Kick is actually only a 2HKO, but Aurorus cannot OHKO it, thus a better option is recommended.
Gym #7 - Olympia (Anistar City, Psychic-type): Return OHKOs Sigilyph cleanly and also 2HKOs Meowstic, which needs way too many Calm Minds to actually threaten Aurorus. Slowking has Power Gem, but Aurorus outdamages it with Thunderbolt; however, both are 3HKOs, and Slowking has Yawn as well. Thunder Wave could help Aurorus fight Slowking if healing items are allowed; preventing it from hitting on occasion will keep Aurorus just healthy enough to survive the fight.
Lysandre battle #1 (Lysandre Labs): Mienfoo's High Jump Kick is a killer, but Murkrow's Steel Wing actually cannot kill Aurorus, unless it scores a critical hit with a higher than average damage roll. Pyroar can be 2HKOed with Ancient Power, but two Fire Blasts may kill with high damage rolls, whether due to a critical hit or a burn; if there is a Pokémon on the team that is free from this risk, it should be used instead. Gyarados can straight up kill Aurorus with Iron Head; avoid.
Aliana (Lysandre Labs): Return 2HKOs Mightyena easily and will also score the OHKO against Druddigon, if Aurorus is holding the Expert Belt.
Celosia (Lysandre Labs): Manectric is easy to beat, but Drapion represents a threat: its Acupressure could pull unexpectedly tricky stat boosts, delaying Aurorus' Return 3HKO by several turns and then beginning to threaten the rest of the team as well. If there is a better option to deal with Drapion, it should be picked.
Bryony (Lysandre Labs): Liepard is no trouble, but Bisharp will straight up kill Aurorus with Iron Head. Avoid it.
Mable (Lysandre Labs): Ancient Power disposes of Houndoom in two turns, even if it uses Snarl once. Weavile has Low Sweep, however, and while Aurorus can take one hit from it, it will OHKO if it scores a critical hit and there is not much Aurorus can do, as even Ancient Power is a 2HKO not even close to OHKOing.
Xerosic (Lysandre Labs): Crobat's Steel Wing actually cannot kill Aurorus even with a critical hit, unless its Defense is fairly lower than average, whereas Aurorus' Return throws the bat right out of the window. Malamar's Superpower, however, will destroy Aurorus if it attempts to fight it.
Lysandre battle #2 (Team Flare Secret HQ): Avoid Mienshao now more than ever, and Honchkrow as well, since a critical Steel Wing will kill Aurorus. If this risk must absolutely be taken, Return will OHKO, but it is not recommended. Either use caution against Pyroar, or bring the necessary healing items, or a counter to switch to if Aurorus is in trouble; Fire Blast can still prove insidious. Gyarados has Iron Head, and is thus off limits.
Xerneas (Team Flare Secret HQ, X only): Aurorus cannot hope to defeat Xerneas, as its Moonblast comes close to 2HKOing in its natural state, and a single Geomancy will make it a certain kill. Aurorus' Return cannot 2HKO, either.
Yveltal (Team Flare Secret HQ, Y only): A much better matchup than its alternate version representative: Yveltal can be 2HKOed easily with Return, and its Dark Pulse is only a 2HKO. A critical hit will still kill Aurorus, but if healing items are allowed in arbitrary quantities, Aurorus can paralyse it with Thunder Wave and then heal until paralysis kicks in, avoiding untimely critical hits before using Return.
Lysandre battle #3 (Team Flare Secret HQ): Mienshao's High Jump Kick is off limits for Aurorus, as should be Honchkrow with its Steel Wing, as critical hits from that move can still kill Aurorus; Aurorus can OHKO back with Return, but this is risky. Pyroar is relatively strong, but can be defeated with the support of some healing items. Mega Gyarados still has Iron Head and an even higher Attack; do not fight it.
Professor Sycamore (Couriway Town): Aurorus can take even a Petal Dance from Venusaur, and OHKO it with Return; it will not be able to stomach a critical Petal Dance, however. Charizard hardly deals damage even with Flamethrower, and is destroyed by Ancient Power. Aurorus should not fight Blastoise: its Aqua Tail is a likely 2HKO, as is Aurorus' Thunderbolt, but Blastoise is also likely to outspeed.
Shauna (Route 19): Delcatty and Goodra get nuked by Return; even if Goodra outspeeds, its Earthquake is only a 3HKO against Aurorus. Aurorus should not attempt Chesnaught, though, as it cannot OHKO with Ice Beam and Chesnaught can with Brick Break. Greninja's Water Shuriken also only chips away a little over half of Aurorus' health with five hits, and Thunderbolt 2HKOs it. Delphox can be 2HKOed with Ancient Power if Aurorus is still healthy, as Psychic is a 3HKO.
Tierno (Route 19): Aurorus destroys Talonflame with Ancient Power and can take a Petal Dance from Roserade, too, then KOing with Return. Thunderbolt 2HKOs Crawdaunt, as does its Crabhammer; Aurorus can win, especially since Crawdaunt is slightly slower, but it should not start the fight against Crawdaunt anywhere below full health.
Trevor (Route 19): Return OHKOs Aerodactyl and 2HKOs Raichu and Florges. None of them can do better than 3HKOing Aurorus.
Gym #8 - Wulfric (Snowbelle City, Ice-type): Aurorus can OHKO Cryogonal with Rock Slide after taking a Flash Cannon, or 2HKO Avalugg with Ancient Power after taking a Gyro Ball. Cryogonal can kill with a critical hit, but Avalugg cannot, and is therefore the safest to fight. Aurorus should not attempt Abomasnow, whose Energy Ball can two-shot before Aurorus gets to do the same.
Rival (Victory Road): Aurorus 2HKOs Meowstic and Absol with Return, which also OHKOs Altaria. Vaporeon's Muddy Water cannot be outmatched, but Jolteon and Flareon can be respectively 2HKOed by Return and OHKOed by Stone Edge; Jolteon's Double Kick can KO Aurorus only in three turns. Delphox can be beaten easily with Rock Slide or Stone Edge, both 2HKOs, but Chesnaught will flatten Aurorus with Brick Break and the matchup against Greninja is entirely up to chance, as its Water Shuriken scores a two-turn KO with 8-10 overall hits and Freeze-Dry only 2HKOs; Greninja should preferably be left to another Pokémon.
Elite Four Wikstrom (Pokémon League, Ironworks Chamber, Steel-type): Aurorus is helpless against all but Probopass, which it can outspeed and 2HKO with Earthquake, since Probopass' Flash Cannon is also only a 2HKO.
Elite Four Malva (Pokémon League, Blazing Chamber, Fire-type): Pyroar's relatively non-threatening Flamethrower leaves Aurorus wiggle room to set up Calm Mind. At +2, Ancient Power can OHKO all of Malva's Pokémon.
Elite Four Drasna (Pokémon League, Dragonmark Chamber, Dragon-type): Expert Belt-boosted Return OHKOs all of Drasna's Pokémon.
Elite Four Siebold (Pokémon League, Flood Chamber, Water-type): All of Siebold's Pokémon can outspeed and 2HKO Aurorus, so they should all be avoided with the exception of Gyarados; Aurorus can survive a non-critical Waterfall and then OHKO with Freeze-Dry.
Champion Diantha (Pokémon League, Radiant Chamber): Since Aurorus' weakness to Flying Press is not two-fold, it can survive a hit - even two, in some cases - and OHKO Hawlucha back with Return. Tyrantrum will, however, OHKO with Head Smash before Aurorus does so with Ice Beam. Diantha's own Aurorus offers a good setup opportunity, allowing Aurorus to Calm Mind at will, as Diantha's Aurorus can only 4HKO with Thunder on average and only before any Calm Minds are used; a setup of at least +4 is recommended, due to the threats the rest of Diantha's team is capable of posing. At +4, Diantha's Aurorus can be OHKOed with Ancient Power; Aurorus can then take a Seed Bomb from Gourgeist and OHKO with Ice Beam. Neither Goodra nor Mega Gardevoir will deal significant damage with such a boosted Special Defense, and Aurorus will easily KO them; even Goodra's Focus Blast is only a 3HKO at that stage, though of course, a critical hit will still end Aurorus.
Post-Game: As per usual, Aurorus should be kept away from any Pokémon that may have non-ridiculous Fighting or Steel coverage; if that is done, it should survive without a problem.
Amaura's initial moveset consists of Icy Wind, Take Down, Mist and Aurora Beam. Note that, due to its ability Refrigerate, this can be effectively considered a mono-Ice moveset, with Take Down being its strongest move. Amaura learns Ancient Power at level 26, which is very good for STAB; then, it gets Round at level 30, which is actually better than Aurora Beam due to the Refrigerate boost, but may not be better than Ice-type Strength for Adamant specimens (or with otherwise low Special Attack). Avalanche comes at level 34; it is not bad, but not incredible either, due to running off Amaura's lower offensive stat. Hail comes at level 38; also not a bad move, but with Aurorus' great movepool, it will find it difficult to deserve a moveslot. After evolution, Aurorus gets Nature Power at level 43, which will turn into Refrigerate-boosted Tri Attack in plain terrain or buildings, and Energy Ball in the tall grass; although situational, it can become a handy coverage move to use. Then, it learns the useless Encore at level 46, and finally a better move in Light Screen at level 50 which, however, will once again compete for better coverage, unless the set Aurorus is running is built to be defensive. Ice Beam finally comes at level 56. Hyper Beam, at level 63, is an extremely powerful option, once again thanks to Refrigerate, but one that is also very risky and not recommended at all: due to Aurorus' low Speed, it will likely take two turns of damage (attack and recharge) and its many weaknesses pose a real threat to its safety for a number of switch-ins. If you ever train that far, Aurorus also gets Blizzard at level 74 and Freeze-Dry at level 77, neither of which is a particularly interesting option, except the latter in a limited amount of cases; Freeze-Dry will not find much room, as Aurorus is weak to Water and slow.
Aurorus' TM pool is incredible. It gets a wonderful setup move in the form of Calm Mind after the Olympia fight, and plenty of special moves to back it up: Thunderbolt or Thunder for general coverage, or even Charge Beam as a Calm Mind replacement to save a slot; Dark Pulse, which deals with Psychic- and Ghost-types very well; Flash Cannon, unfortunately a postgame exclusive, for Fairy coverage; Psychic, useful against Poison-types, though not much so otherwise. It also has a number of physical options: Rock Slide or Stone Edge for physical Rock STAB, the latter of which is much more powerful (though also less accurate) than Ancient Power; Bulldoze, as a middle-game coverage move for Electric-types; Dragon Tail, to force switch-outs against enemies that may have started setting up. For physically-oriented specimens, Ice-type Return is an excellent move to have, sitting at base 130+ power before STAB. Aurorus can also run a support and/or stall set with status moves such as Toxic and Thunder Wave, support moves like Reflect and Light Screen (also learnable by TM, but the TMs are exclusive to the postgame), and even the weather move Sandstorm which, aside from dealing steady chip damage, also boosts its already amazing special bulk.
Offensive: Calm Mind, Nature Power / Ice Beam, Thunderbolt / Freeze-Dry, Ancient Power / Dark Pulse
Support: Toxic, Sandstorm, Nature Power / Ice Beam, Light Screen
Fighting-types: Aurorus' Steel dilemma can be resolved non-redundantly only by Fighting-types, which do not share any weaknesses with Aurorus. Fighting-types also sport a welcome Steel resistance, which Aurorus will appreciate if it needs to switch out of battle.
Psychic or (dual) Fairy-types: Fighting-types are best covered by Psychic- or Fairy-types, both of which have super effective coverage to hit them with, and resist their STAB. Since Kalos is fairly full of Fighting moves even on Pokémon that do not get STAB on it, it is essential to have a Fighting resist on the team. Since Aurorus is also doubly weak to Steel, Fairy-types should only come on board if their secondary typing compensates for the Steel weakness; otherwise, Psychic-types should be preferred.
Grass-types: Grass is the best type to cover for all of Aurorus' non-double weaknesses. Rock, Ground and Water are all disposed of easily with Grass moves, and there is no shortage of Grass Pokémon in Kalos. Dual Grass-types should preferably not have any weaknesses in common with Aurorus, however.
Fast hitters: Aurorus has good stats all across the board, with the sole exception of Speed. A fast Pokémon is recommended on the team, as matchups can happen in which hitting first is the key to victory.
Minimum stats are calculated with 0 EVs, IVs of 0, and a hindering nature, if applicable.
Maximum stats are calculated with 252 EVs, IVs of 31, and a helpful nature, if applicable.
Amaura Line Ratings
What Nature do I want? Speed is the only stat that Aurorus will hardly ever need, even as Amaura. Boosting Special Attack is most beneficial in the long run, but an Attack boost will not be unwelcome during training; as such, the best natures to have are Quiet and Brave, with the defensive options - Relaxed and Sassy - coming up second.
At what point in the game should I be evolved? Aurorus should be fully evolved either before or right after the Clemont battle.
How good is the Amaura line in a nuzlocke? Aurorus is not that difficult to use, but it is difficult to keep alive without a scare. It can take most super effective moves that are not Fighting or Steel, but with the many Fighting TMs and Steel Wing existing, an inexperienced player may unexpectedly run into the one trainer with more coverage than average, and a damaged Aurorus - Amaura even more so - will suffer from one such surprise. Essentially, Aurorus is the ideal match for players who know the region very well: if you can put all the Low Sweeps and Iron Heads on a map, then Aurorus is the 'mon for you.
Weaknesses: Ground, Rock, Water, Grass, Fighting (x4), Steel (x4)