Is a Hero's per-Bystander Attack bonus fixed when the card is played, or does it grow with rescues later in the turn?

Question

Accepted Answer

It is fixed when the card is played. A bonus like Black Widow's counts the Bystanders you have at that moment, so later rescues add no Attack. Only 'whenever' effects keep triggering for the rest of the turn. A copied hero's value follows the hero underneath it when that hero changes.

Legendary: A Marvel Deck Building Game

Is a Hero's per-Bystander Attack bonus fixed when the card is played, or does it grow with rescues later in the turn?