Strongest Legendary Pokemon of Each Region

Source: Serebii.net

Kanto: Mewtwo

For the longest time, Mewtwo stood as the single most powerful Pokémon, representing both an a achievement and living nightmare of scientific progress. Nothing could stand up to Mewtwo and hope to win alone, and the combination of Psychic's few resistances and Recover made defeating Mewtwo a losing battle. The goal of creating the world's most powerful was seemingly achieved. However, as more Pokémon began to be discovered it became more apparent that Mewtwo was not quite all-powerful, and that the gods and super titans of the Pokémon world could easily stand up to or even outmatch this monstrosity of scientific progress. Meanwhile its title of “world's most powerful Pokémon” was found to already belong to a sky dragon that preceded Mewtwo's existence by several hundred million years. While time has exposed that Mewtwo is not quite the unstoppable monster that people once believed it to be, it's still an incredibly powerful threat that should never be taken lightly. Incredible Speed and Special Attack are its two most distinguishing traits and not many Pokémon can match up to that power, while a huge movepool lets it threaten a wide variety of threats. Mewtwo also stands as one of two overwhelmingly powerful legendaries to gain the power of Mega Evolution, and one of two Pokémon in general to obtain two different Mega Evolutions. All of this undoubtedly makes for a huge threat, but there are several factors that continue to keep Mewtwo in check. Most significantly, Mewtwo's Psychic typing is no longer the same dangerous type it was back in during the years of its creation. Weaknesses to Dark and Ghost are very problematic since moves like Sucker Punch and Shadow Sneak overcome Mewtwo's fantastic speed while picking away at its less than spectacular bulk, and Pursuit makes it regret trying to escape from a dangerous situation. Furthermore it lacks many resistances to dangerous types which makes it difficult for Mewtwo to directly switch into powerful threats in a world where everything hits equally as hard as Mewtwo itself. Make no mistake though, Mewtwo still certainly has a place in a world dominated by gods and titans like Arceus, Mega Rayquaza, Xerneas, Primal Groudon and Primal Kyogre, though the days of Mewtwo laying waste to everything in its path are long gone.

As one of two Pokémon to obtain two different Mega Evolutions, Mewtwo manages to find ways to further diversify its abilities. As with any Mega Evolution, the power boost raises Mewtwo's base stat total to a staggering 780, surpassing all other Pokémon and only being matched by a divine being known as Mega Rayquaza. Mega Mewtwo X in particular completely changes Mewtwo's fighting style, giving it a greater focus on physical power and turning it into a dual typed Psychic/Fighting Pokémon. Unlike most Psychic-types, Mewtwo also has the physical movepool to support a physically based Mega Evolution, so the unpredictability of whether it runs a physical set or special set makes it a bigger threat than it already was. Moves like Low Kick, Zen Headbutt, the elemental punches and even rarities like Self-Destruct give Mewtwo plenty of options to threaten opponents just as it would with special moves, and with one of the highest Attack stats in the game it has more than enough power to take full advantage of its newfound power. Mega Mewtwo X also has the added bonus of maintaining its naturally high Special Attack, so it's still capable of throwing its opponents off-guard with special moves like Focus Blast, adding an extra layer to the mindgames that Mewtwo already provides. However, despite the incredible power that its Mega Evolution provides, Mega Mewtwo X is not without notable shortcomings. While a Psychic/Fighting typing grants it a very useful neutrality to Bug and Dark type moves, added weaknesses to Flying and Fairy are very dangerous in a world dominated by Xerneas, Mega Salamence, and on an even higher plane, Mega Rayquaza. In addition, it faces competition for the Mega slot by more threatening Megas such as the aforementioned Mega Salamence and Mega Rayquaza which boast a more useful Dragon/Flying typing. It still lacks many resistances and is not much bulkier than normal, so powerful neutral attacks still put Mewtwo at risk of taking huge damage. Its STAB moves are also varying in usefulness since Low Kick doesn't do much damage to lighter opponents and Zen Headbutt is not a particularly strong move, so while they're effective at hitting a select group of Pokémon this also makes it easier to wall with options like Lugia, Giratina, Aegislash and Mega Sableye around. Shortcomings aside though, Mega Mewtwo X adds a dangerous layer of diversity to Mewtwo's impressive repertoire, and it's one you should never ignore when facing this genetic monstrosity.

Originally revealed as Mewtwo's awakened form, Mega Mewtwo Y can easily be described as such. This Mega Evolution takes Mewtwo's famed Special Attack and Speed and boosts them even further, making for a lightning fast and incredibly powerful special attacker, claiming the title of highest Special Attack among all Pokémon. Everything that was true about Mewtwo before still stands, its wide movepool helps it threaten a huge range of threats and its Speed is almost unmatched, with a small boost to take it even further. A boost to its Special Defense also makes it a more effective Calm Mind user than it would be in its normal form. However, as with many Megas introduced before ORAS, Mega Mewtwo Y obtained a few questionable stat changes that serve to hurt it more than anything. A significant boost in Attack does no favors for Mewtwo, only making it more vulnerable to Foul Play, while a decreased Defense stat means it has even more trouble taking physical hits than it already does, especially with powerful priority users to bypass Mewtwo's incredible Speed. Furthermore, all of the problems that trouble Life Orb Mewtwo still hold true, so its typing means it has trouble finding switch-in opportunities while weaknesses to Shadow Sneak and Sucker Punch means it still needs to be careful around Ghost and Dark types. As with its Fighting-type counterpart, Mega Mewtwo Y also faces competition for the Mega slot, which becomes even more difficult when Life Orb Mewtwo hits slightly harder than its Mega Evolution does without using the Mega slot. However, that isn't to say that Mega Mewtwo Y is worse than its normal form, as the speed, power and special bulk go a long way in giving Mewtwo justification to use its awakened form. Even with the competition and weaknesses it has, Mega Mewtwo Y is still a worthy advancement from this genetic experiment's creation. It might not descend from the heavens to lay waste to everything its path the same way Mega Rayquaza does now, but Mega Mewtwo Y is not a threat you should ever take lightly.

Johto: Lugia

Lugia takes hits like a planet. It takes a lot to hurt it badly. It has loads of support options, and can even go offensive if you want to surprise the opponent. Amazing stats, amazing movepool; Lugia is a great choice for a physical wall on your uber team.

Hoenn: Rayquaza

Rayquaza is a Pokémon that Game Freak has always given amazing treatment, even among other legendaries. Getting shiny event distributions and claiming Victini's signature move V-create isn't something that just any Pokémon can hope for without insane popularity backing it up. Rayquaza gets all of that and more with the treatment it gets in other games and the anime. Make no mistake though, having one of the coolest shiny forms and stealing signature moves isn't just for show. Only something with incredible strength can handle babysitting for titans like Groudon and Kyogre, and Rayquaza certainly wastes no time punishing them for their constant temper tantrums. Even if your name isn't Groudon or Kyogre though, this dragon is something you never want to let catch you unprepared since all it takes is one wrong move for Rayquaza to start tearing things apart. Titanic dual 150 offenses are nothing to ignore and with a movepool that gives it just about anything it could ever need, you can be sure that taking a hit from this monster isn't going to be pleasant. Access to both Swords Dance and Dragon Dance also lets it boost its already huge Attack stat to frightening heights fitting for the Sky High Pokémon, so walling it is no simple task. If that isn't strong enough for you, ORAS was kind enough to give it a shiny new signature move in the form of Dragon Ascent, and being a Flying type move rather than Dragon type means that not even Fairies are safe from its overwhelming power. On top of that, Rayquaza's new Mega Evolution has allowed it to ascend to unprecedented heights that not even Arceus has achieved. However, while defeating Rayquaza might sound like an impossible task, it's not invincible. Only slightly above average speed and unspectacular defenses can make it difficult to set up against the myriad of faster legendaries, and weaknesses to Stealth Rock and common attacking types like Ice and Fairy means that there's plenty of things keeping Rayquaza in check. Just hope it doesn't Mega Evolve against you.

Scientists in the Kanto region once set out to create what they believed would be the world's most powerful Pokémon. When they created Mewtwo, people had believed that their mission succeeded as none of the discovered Pokémon at the time could come close to matching Mewtwo's power. However, several hundred years before Mewtwo was created, the Draconid people of the Hoenn region had already witnessed the true power of a Pokémon more powerful than Arceus itself. That Pokémon is Mega Rayquaza, a Pokémon revered as the savior for aiding the people of Hoenn in their darkest hour and putting a stop to the destructive battle between Groudon and Kyogre. This magnificent dragon sits atop its throne in the sky as the single most powerful Pokémon in the game, capable of wiping out entire teams of even the most powerful legendaries all on its own. Its stats alone are enough to leave some of the most fearsome and intimidating Pokémon quaking in fear, sporting the highest combined offenses in the game at an even base 180 in both Attack and Special Attack. An impressive base 115 Speed also remedies Rayquaza's biggest flaw, turning it into a blazing fast sweeper that very few viable Pokémon can naturally outspeed, and that's only if it doesn't boost its own Speed first. Its ability Delta Stream also summons powerful winds that make it more difficult to take down by reducing all of its Flying type weaknesses, forcing you to rely on Dragon, Fairy and a reduced Ice weakness to hit it for super effective damage. However, what ultimately secures Mega Rayquaza's spot on the throne is its unique ability to store the energy required for Mega Evolution within its body, allowing it to Mega Evolve without the need of a Mega Stone and ultimately hold any item it wants. A Pokémon boasting a 780 base stat total with the ability to hold any item is undoubtedly a terrifying thought, and Mega Rayquaza turns that thought into a living nightmare that nothing in the game can properly counter. If Mega Rayquaza accepts you as its ally you have the world's strongest Pokémon on your side, but if for any reason you incur Mega Rayquaza's wrath, there is no hope left for you.

Sinnoh: Arceus

All hail the great lord and creator. May his blessings shine upon you. Arceus, often dubbed as the “god” of Pokemon, is certainly an amazing beast. With a “perfect” stat spread of base 120 across the board, an ability that lets it be literally any single type it wants, and a movepool chocked full of options to let it abuse those stats and types, Arceus is as versatile as it is deadly. Arceus even once boasted the highest base stat total in all of Pokemon at an unprecedented 720! ...Although, with the advent of Gen 6, things such as Mega Rayquaza, both Mega Mewtwos, and the Primal Reversions managed to edge Arceus out with higher base stat totals. This is of relatively little consequence though, as it is still in possession of the highest base stats of any non-mega and non-primal Pokemon. And in fact, Gen 6 did give it a new toy as well in the form of the Pixie Plate, allowing it to add Fairy type to its repertoire as well. However, even god has some faults, and in Arceus’s case, it does have to contend with limited item options, as it can’t hold anything other than a plate if it’s anything other than Normal type. That said, Arceus is still absolutely one of the most devastating and lethal Pokemon in existence, and only a handful of Pokemon (many of which are Mega or Primal) can match its might. Not only that, but there does not exist any Pokemon that can claim to counter or even check every form of Arceus. If you take Arceus lately, it can and will remind you of why it is the Alpha Pokemon. All things began from Arceus, and it can make sure that all things end with Arceus as well!

Unova: Kyurem

Kyurem is an odd case within legendary trios, both design-wise and stat-wise, and even simply from the perspective of Dragon-type legendaries. Right off the bat you can tell that Kyurem is meant to be an incomplete Pokémon, an empty husk of a dragon that somehow has a will of its own and an unusual stat spread that at first glance is just a bulkier but worse Rayquaza. For a legendary, there isn't much great about Kyurem, and even compared to normal Pokémon it doesn't impress too much. With all that said, Kyurem isn't particularly bad in its own right, at least for what's supposed to be a living empty husk. Respectable mixed offenses and decent Speed allow Kyurem to function as a decent wallbreaker, while a huge HP stat lets it take hits despite the unfortunate defensive traits of an Ice-type. While Dragon / Ice is somewhat redundant offensively, Ice offers great offensive pressure while Dragon typing prevents Water-types from being able to freely come in and wall Kyurem. A useful range of resistances due to its Dragon typing also allows Kyurem to find opportunities to switch in safely despite Ice-types complete lack of defensive advantages, though its weaknesses to common types such as Rock-, Fighting-, and Fairy-types give Kyurem an equally difficult time. Taking things a step further, Kyurem is also unsurprisingly outclassed by its own "complete" formes, as Black Kyurem is a far better physical and mixed attacker while White Kyurem is a better special attacker. While Kyurem itself isn't necessarily a bad Pokémon in its own right, chances are you should look into one of its other formes if either of the two are available options.

Black Kyurem is definitely a contender for "Most Menacing Pokémon" with those huge claws and a face like. When fused with Zekrom, Kyurem becomes a physical powerhouse with one of the highest Attack stats in the game, making for one dangerous physical wallbreaker. In a 3v3 environment, it definitely is a terrifying presence that Battle Spot is glad it never needs to deal with. However, in a broader 6v6 environment, Black Kyurem has significantly more issues that make it a far more manageable monster despite its monstrous 700 base stat total, namely its physical movepool. While it has all the Dragon-type moves it would ever need, Black Kyurem lacks any sort of reliable physical Ice-type move to abuse that monstrous base 170 Attack stat, ultimately making it realistic to keep this monster in check with regular Pokémon. The introduction of Fairy-types took this further, giving us more ways to keep this monster in check. However, that isn't to say that Black Kyurem is not a dangerous threat. While it doesn't quite measure up to the destructive force of Legendary Pokémon like Mega Rayquaza or Xerneas, Black Kyurem is definitely a top level threat in standard play, maintaining similar bulk and Special Attack as regular Kyurem while gaining access to Fusion Bolt as a physical move. For all intents and purposes, Black Kyurem is more or less a better version of Kyurem, as you might expect from a fusion between Kyurem and Zekrom. It might not be the killer Ice-type legendary people expected from BW2, but Black Kyurem is definitely not a dragon you ever want to take lightly.

White Kyurem might not appear quite as menacing or deadly as Black Kyurem, it more than makes up for that with its huge Special Attack that can more effectively abuse its great special movepool. Out of all three formes, White Kyurem stands out as the most dangerous in battle due to the fact that it actually has an Ice-type STAB to make use of. While it suffers from Bad Signature Move Syndrome like its other formes, White Kyurem's great special movepool makes up for it, and with a mirror image of Black Kyurem's stat spread, it's more or less a special variant of Black Kyurem with a better movepool suited to its stats. However, while it's far too much for standard formats to handle, White Kyurem is also by no means an unstoppable powerhouse, and pales in comparison to titans like Mega Rayquaza, Xerneas, and Primal Groudon. Its Speed may be less of a hindrance due to the lower average Speed of legendaries, but it still leaves a bit to be desired with the likes of Darkrai, Mewtwo, and both Latios and Latias. The aforementioned Xerneas also causes major issues for White Kyurem, since its presence alone makes it difficult to abuse its hyper-powerful Draco Meteor to its fullest potential. White Kyurem might be much better off than Black Kyurem due to its more dangerous stat spread, though it seems that no matter what Kyurem does, there's always someone out there to give it a difficult time. Don't let that be a reason to underestimate White Kyurem though, as it can quickly become a huge threat if you're careless.

Kalos: Xerneas

Xerneas, X's cover Pokemon, is quite simply a beast. Amazing offenses, high HP, good enough defenses, and a Speed stat that keeps it ahead of many other Ubers do it a lot of favors. Not only that, but this thing's signature move, Geomancy, is terrifying in the right hands, giving Xerneas the equivalent of two Quiver Dances. This move is the reason why Xerneas is one of the few viable users of Power Herb, as without it Xerneas is a sitting duck while it charges. Add an ability that gives it a big boost to its STAB Fairy-type moves to make up for the lack of an item, and you've got a legend for the ages.

Alola: Zygarde (Zygarde isn't good without its Complete forme, which is not available until Alola)

Zygarde-Complete has been blessed with a 216 in HP, making it quite possibly the bulkiest Dragon type.  Add to this EVs and you've got an invincible Pokemon.  This high HP stat allows Zygarde to tank some hard hitters like Rayquaza and Mewtwo.