Esior, Wardwing Familiar

Spells that target more than one commander you control cost only {3} more to cast.

To determine the total cost of an opponent's spell that targets a commander you control, start with the mana cost or alternative cost that player is paying, add any cost increases (such as that of Esior's middle ability), then apply any cost reductions. The mana value of the spell is determined only by its mana cost, no matter what the total cost to cast the spell was.

If something refers to your commander while you have two commanders, it refers to one of them of your choice. If you are instructed to perform an action on your commander (e.g. put it from the command zone into your hand due to Command Beacon), you choose one of your commanders at the time the effect happens.