>>54501835This is a tough call. Taking over the world isn't a small feat. Elemental birds or some golems aren't going to cut it. The first potential option are the lake trio. Mexsprit can mindrape people, Uxie can mindwipe people, and Azelf can mindcontrol people. If you were smart and careful enough to use this you could slowly twist the ruling class to your whims, and rule the world via a shadow government as a puppet master. However, this would require incredible amounts of political and economical knowledge and have multiple points of potential failure, aswell as be limited in scope to only what world governments are capable of implementing. The brute force method is more straightforward with far less gears turning that could go wrong, and has a bigger upside, since you could force whatever changes you want. But taking on world militaries isn't something some bargin bin sword of justice can handle. Groudon and Kyogre could probably manage, but they'd end up doing more harm than good with how devastating they would be to the planet's environment. Rayquaza has potential but he's more of a single target fighter, and lacks the widespread destructive potential of his counterparts necessary to swiftly dispatch large ground forces.
As such, the best mon for the job is Zekrom. Zekrom and Reshiram are both stated to be able to scorch the world, and judging by what I can only assume are plasma engines on them that seems like it could be an accurate enough assesment. Widespread destructive force without the environmental damage of Groudon/Kyogre. Plus the free Kyurem coupon, while not on the level of Zekrom, is still a heavy hitter, and could assist with an offensive on 2 fronts. In the event you needed even more firepower to evaporate some poor first world country, fusing the 2 is a nuclear option few could match.
Both Zekrom and Reshiram could accomplish this. I chose Zekrom because it's said to be able to create an ideal world. Perfect for a future king.