Hello! I have a question about the 4 options when a character is under attack.
Is the chosen option intended to be a free reaction (besides the Fatigue costs, if any) or does it count as an action?
Getting attacked happens outside of the player's turn, so, without diving into 5E parlance too deep, let's call it a "reaction".
This means that Fighting Back can allow for 2 attacks in quick succession (You get attacked > Fight back, take damage, deal damage back > Your turn now, you can attack back)