There is the Kyogre-shaped elephant in the room, and Gamefreak weirdly slowed on Dragon Ubers after Fairies came into the series, only having Zygarde, Ultra Necrozma, and Eternatus as big names until SV's duo after 3 consecutive generations of prominent Dragon Legends/Ubers (Rayquaza, the Soul Dew Latis, Creation Trio, Tao trio).:XY/xerneas:
Xerneas has always felt like a very intentional inclusion to the franchise for me in the sense that it’s clear it and Yveltal were design to help try and balance out the restricted metagames of competitive play. Think about it- before Gen 6, what were the main two Types people thought about when they thought about big, powerful Ubers-tier Pokémon? That’s right- Psychic and Dragon. The problem begins with Xerneas’s base stats and Geomancy not exactly looking like the kind of thing that would synergize well together. If anything, something that boosts Attack, Special Attack, Speed would have made more sense on paper (think Shell Smash but with different flavor), at least to me. The other issue from a balance perspective is that Xerneas also has the typing advantage over the Pokémon that was meant to balance out the Ubers Psychic-Types, while itself still replicating the niche Psychics used to have of being the game’s primary check to Fighting-Types. Instead, we get what’s basically better Quiver Dance on Power Herb variants that turns Xerneas into a hyper offense stole rather than the bulky offensive utility role you would expect to see from the so-called Life Pokémon.
The end result of Geomancy’s design as a move in combination with Xerneas’s already existing traits is a centralizing metagame force that warped the game around itself. In fact, I can’t remember who first said this, but if anything it would make more sense for their roles in competitive to be flipped and Yveltal to be known as the more aggressive one. At least in casual play and single player environments these issues aren’t nearly as significant. I really respect the different angle Game Freak was going for with this duo and while I think they completely dropped the ball on Zygarde in Kalos specifically (the whole Cells concept makes more biological sense in a climate like Alola’s anyway), I just wish their first attempt at a Fairy-Type legendary wasn’t this weird clash between historic lore inspirations and a misguided competitive mindset.
Although, now that I think about it, since I wasn’t around here until after the XY Xerneas controversy largely subsided, I have to wonder how often people ran Close Combat on Geomancy or Choice sets. I would imagine Focus Blast was more common, but CC would have had the advantage of being a physical move with the better accuracy, which I feel like would have given it a niche for stronger special walls and more consistent Steel coverage like some kind of 3DS take on Iron Valiant.
That said, something I find interesting along this idea of Bulky offense focus as a thought experiment, is HOW they seemed to approach the two mons. Xerneas and Yveltal have identical BSTs, leaving it to type and Movepool to define and differentiate their roles relative to each other. Xerneas actually does have a larger number of non-offense focused moves, relevant or not, such as Light Screen, Aromatherapy, and Misty Terrain, as well as moves to empower itself rather than breakdown the opponent such as Psych Up, Horn Leech, and its signature Geomancy. Yveltal meanwhile is mostly attack focused level up moves, with even its few utility-focused moves being dedicated to inhibiting the opponent's actions with Taunt, Disable, and Snarl's debuff.
In practice, Yveltal actually has the more defensive lean between Roost and Oblivion Wing having a Drain effect, the latter being the STAB not matching Yveltal's Aura boost for damage vs Xerneas's Moonblast (given it has a single STAB). Dark Aura benefits it on moves that it can either use without investing (Dark STAB into a Meta with Ghost/Psychic staples like Necrozma or Calyrex) or even Foul Play, a move that specifically favors use by Bulky Tanks that can take hits from the high ATK they "steal" for it. Xerneas meanwhile ends up playing offensive because its utility options don't really DO anything once it has them up, since you'd usually do it in service of an offense focused partner, rather than just building Xerneas to do that in the first place.
Heck, Xerneas has two very viable boosting options in Calm Mind and Geomancy, while Yveltal only gets Hone Claws, incompatible with its Oblivion Wing STABs (though ironically works with its more utility/counter Playstyle using Sucker Punch and Knock Off later), which is even more curious because compared to the mix of Phys/Spe on Yveltal's level-up moves, Xerneas is almost ALL physical that those boosts would not impact (granted the one Special move is the only one it needs). It makes me almost wonder how Xerneas would have functioned if you reversed that paradigm: If its Fairy STAB was physical like Play Rough to match things like Close Combat and Megahorn, but it could go with a narrower Special movepool to capitalize on Geomancy using Gleam (instead of the strong ST Moonblast option) and a few bits such as Psyshock and Focus Blast.
It's interesting to see the dynamic in practice where not just Xerneas, but BOTH mons were clearly designed for the Playstyle that the other fell into once they met gameplay proper. It makes me wonder if this completely slipped the designers' notice on paper, or if the idea was to give them some side options that ended up defining their roles because they were just better at those particular kits.



