The Ethereals change is a great idea, but not so great is the effect used to represent them. It makes it difficult to differentiate the Illuvials on the board at a glance and leads to being more reliant on the stats panels, which seems like bad UX.
Some options:
- Showing the Illuvials as ethereal when the battle is playing out may not even be necessary. Just make it known before the user goes into the battle.
- Have a button to toggle ethereal mode on or off
- Use a different effect that doesn't alter the color scheme of the Illuvials.
- Use an icon over their heads or in the panel somewhere.