So what ever happened to Lysandre? A lot of people speculate that he stayed dead or immortal (depends on the version) under the ultimate weapon in Geosenge Town but Professor Sycamore says this in Couriway Town
>I'm sincerely grateful for what you did for all of the Pokémon and people of this world. And by stopping Team Flare, you also saved Lysandre.

Strange thing to say if he was either dead or missing
What if he survived and to atone for his sins he changed Team Flare into Quasar and he is the one who goes with the Urban Redevelopment Plan to create a more beatiful Lumiose. Remember what the teaser said?
>A vision of beautiful coexistence between people and Pokemon
And what was the Evolution's special XY episode title? The Visionary. And it was about Lysandre. And what this visionary wanted? A beatiful world.