There's currently an event going on: a CYL browser game!
https://events.fire-emblem-heroes.com/color
It's a simple reaction time game, where you have to pick the correct CYL unit to counter enemies. Make sure to shoot fliers with Lyn too, though.
Getting over 1,500 points nets you a CYL Lucina wallpaper. Perhaps this changes daily for the other units.
In addition, named units will occasionally show up in the browser game, a lot more often on Lunatic. If you can encounter and defeat all of them, you get a special wallpaper! This might be rotated daily too.
If the global score reaches 1,500,000,000 or above, everyone gets 10 orbs and 5000 feathers! There are smaller rewards too, but who cares lmao.
Seen enemies so far:
- Elise
- Leo
- Tharja
- Hector
- Camilla
- M!Robin
- F!Robin
- Takumi
- Ike