A bit of a peeve with X and Y, even though I like the games, but one of the big things that annoy me about the story/plot of X and Y is Xerneas and Yveltal. And that is the fact that Xerneas and Yveltal are mandatory captures in X and Y.
I don't mind legendary captures being mandatory, and I'm inclined to catch them anyway, but the reason it annoys me here specifically with X and Y is that the game does not give any sort of justification as to why Xerneas and Yveltal want to join you or aid you in the first place. Not only do they not show up at all until you first encounter them, but the game doesn't allude to their existence much at all beforehand, and it just shows up and awakens in front of you and mandates that you capture it. It does not build up well at all and the legendary just shows up suddenly and you catch it.
Yes, other games since Gen 5 have made the cover legendary required to be caught. But there was a good build-up to and in-story justification for it.
- Reshiram and Zekrom are heavily talked about in great detail in the story of BW1. The game talks about how they split in two, chose one of two heroes who quarreled, and sided with them and fiercely fought alongside them as their allies. It's clear that Reshiram and Zekrom each are inclined to choose a hero who represents truths or ideals, and fights valiantly on their behalf: that's their schtick. Just as one of the legendaries chooses N, the other chooses you, the player (aka Hilbert/Hilda), and once you've shown you are commited to fighting for truths/ideals, the legendary awakens, and as N translates what they're saying, it wants to test you and be friends with you, and fight alongside you. This was the first time they did mandatory captures of the cover legendaries, and they did it well.
- Solgaleo and Lunala are a distinct case of a Legendary Pokemon where you meet the individual you end up catching from the beginning of the story. That is, in the form of their base unevolved form, Cosmog, as Nebby. The little Cosmog that Lillie carries around, you gradually bond with it over the course of the game from the beginning when you first protect Cosmog, and later meet up with it and Lillie on numerous occasions and steadily grow closer to it, it goes through quite a bit especially when Lusamine tries to use it to summon UBs, and then when you need to summon the legendary to get to Ultra Space, it awakens and reveals itself to be the Legendary Pokemon, and it helps you and Lillie to get to Lusamine in Ultra Space. Now that it's evolved into the Legendary, you already have a strong connection with it, and now you capture it so that you take it with you for the rest of your journey. In other words, you effectively form a bond/connection with this Pokemon over time.
- Zacian and Zamazenta are a bit of a lesser scale, but you and Hop meet one of them once early in the game, later discover their existence, and then when the Darkest Day happens, you manage to summon them and fight alongside them to stop Eternatus. And then later on you meet them again when the Sordward and Shielbert weirdos try to force them to do evil things, and one of them steps in the way, and they recognize you and it reveals it wants to test you and see if you're worthy of its friendship. So in a way, you also gradually build a connection with the Legendary Pokemon, and so does Hop over the course of the story, both of you becoming close allies of the wolves.
When you look at it, Xerneas and Yveltal in X and Y really stick out like a sore thumb. The other cover legendaries since then have that sort of build-up and/or in-game lore and justification that makes the event of needing to capture them and take them with you on your journey a meaningful event, and you have a formal connection with the legendary, either as the Chosen Hero or even just a friend. Meanwhile, Xerneas and Yveltal have no build-up to their capture whatsoever, they just show up on a whim, there's no in-game justification of why you are required to capture them, and they are barely alluded to beforehand. It's just a very odd design choice and it really feels like in this case they made them mandatory captures for the sake of it, without trying to make it a meaningful event like Reshiram and Zekrom before them, or even the other cover legends (like Solgaleo and Lunala/Zacian and Zamazenta) that came after. X and Y's story has plenty of issues besides this, but this is one that really sticks out to me.
