Can Zenith Blade target a friendly unit that is already at the same battlefield as the stunned enemy unit?

Ruling: You can target a friendly unit at the same battlefield as the stunned enemy unit because Zenith Blade's move is a "may" effect, so no illegal action has been attempted yet during targeting. However, during resolution, you cannot choose to move that unit to the same battlefield it's already on, as that would be an illegal choice.

Sequence:

• During targeting, you can choose a friendly unit at the same battlefield as the stunned enemy
• During resolution, you must choose not to perform the move (using the "may" option)
• You cannot attempt to move a unit to the same location it already occupies

Nuances:

• The legality is evaluated differently during targeting versus resolution because of the "may" clause
• The move is not "deterministically illegal" during targeting since there's a choice to be made during resolution
• This differs from situations where you try to target something illegal and make it legal via reaction, which is not allowed