Pokémon Legends Z-A was announced for release in 2025, and I was surprised, but extremely happy for a return to Kalos... at least partly.
According to the game's blurb from Nintendo, the game will be entirely within Lumiose City, the central hub of Kalos. Mildly disappointing, sure, but considering Legends Arceus seemed to be Game Freak's take on Breath of the Wild-style gameplay, my guess is Legends Z-A will be their take on FF7: Remake -- a game set entirely within one city with multiple sectors. Lumiose has multiple avenues and plazas that all have distinct features even in X&Y.
That being said, there's a good chance some X&Y NPCs will make a return, specifically ones with ties to Lumiose. So here's a list I came up with of who they might be, from most-likely to least-likely:
Prof. Augustine Sycamore.
Kind of a given. His lab is in Lumiose, his primary field is Mega Evolution (which was teased to return after being absent since Sword & Shield), and he knows of the Legendary Pokémon of Kalos, revealing to the player the name of the one on the box on their first visit to Dendemille Town. He's also mentioned in the Mega Evolution Tower in Shalour City as not being able to Mega Evolve anything. Maybe that'll change, reflecting his anime counterpart?
Sina & Dexio are Sycamore's primary assistants, also studying Mega Evolution and the Pokémon of Kalos as a whole. They also showed up occasionally as masked heroes to fight Team Flare, but wind up more like that Tuxedo Mask "But you didn't do anything!" meme.
More importantly to Z-A, in Sun/Moon/Ultra Sun/Ultra Moon, they give the player the Zygarde Cube. A box to hold fragments of Zygarde, heavily implied to be the Legendary at the center of Z-A's story based on the logo design. They even help the player join those cells into the 3 main forms of Zygarde: 10%, 50%, and Complete. That being said, their personal experience with Zygarde might come into play.
Gym Leader Clemont is the Leader of Lumiose Gym, within Prism Tower. He also maintains the tower itself, as shown when he restores power to it after the Team Flare-caused blackout.
Clemont is an inventor and is intrigued by technology, though some of his inventions don't go as planned. But, his penchant for innovation and improving things might come into play with the renovations of Lumiose hinted at in the teaser.
Trevor, one of the player's rivals, and a recipient of the Honor of Kalos medal along with the player and other rivals, making him a Hero of Kalos. He lives in Lumiose, and mostly focuses on the PokéDex inspired by seeing a Pokémon when he was little that he didn't recognize. He hoped by completing the PokéDex might answer that question, but that answer is never brought up in X&Y.
So what if that Pokémon was from a later region introduced after X&Y? Or a never-before-seen regional variant? A new Mega Evolution maybe? Lots of possibilities, and chances to expand on that thread.
Alexa of Lumiose Press. She's first introduced in Santalune City, preventing the player from leaving town before beating her sister, Viola, at the Gym. She can later be found at work in Lumiose, and will guide the player to any major location in the city they ask her about, so she knows Lumiose like the back of her hand.
Her role was small, but she was used to introduce Kalos in the anime, being the first Kalosian Ash meets, and she serves as a tutorial character, giving the player the Exp. Share.
Emma and her Espurr, Mimi. Introduced in the postgame, she is central to a subplot with Looker, trying to help solve mysteries around town. But she gets wrapped up in a plot by the remnants of Team Flare by Xerosic. Looker arrests Xerosic and leaves the Looker Bureau, their base of operations, to Emma. And Xerosic leaves Emma some things as well: the Expansion Suit which allows her to perfectly disguise her appearance as anyone, and his party of Pokémon.
Emma was added to Pokémon Masters EX fairly recently, and the helmet to her Expansion Suit was added to Scarlet & Violet's DLC as a costume option. So despite only appearing after the main story was over, she's not forgotten.
Lastly, Malva of the Elite Four, formerly of Team Flare.
We first see her as the anchor of Poké News, announcing that the PokéBall Factory raid by Team Flare was thwarted. Then at the League where she addresses to the player directly about her allegience to Team Flare, and her anger at the player dissolving them. And finally, in the Looker subplot, she meets the player in Lumiose and sells out Xerosic as her end of a bargain with Looker. But she doesn't seem to renounce her past deeds in Team Flare, and threatens that Looker should uphold his end of their deal.
Considering Lysandre Labs, a base of Team Flare's, was beneath Lumiose, it wouldn't surprise me to see some return of Team Flare given that Zygarde resides underground. And the only reason Malva's at the bottom of this list is her specific appearance in Lumiose was situational, as she's not a resident like the others are.
In any case, this is all just guesswork, so I could be way off base. As of me writing up this post, we know very little outside of the first teaser and the blurb from Nintendo. But, it's fun to theorize what could be! Thanks for reading!
