In a 4-player game, if players A and B are in showdown on a battlefield, can player C use a reaction to assign additional damage to one of the units?

Ruling: Yes, player C can interact with a reaction during the showdown between players A and B.

Sequence:

• Priority goes around to all players, not just the attacker and defender
• Every player gets a window of focus (the ability to start chains)
• Each player gets a chance to add items to each chain, regardless of whether they are an attacker, defender, or neither

Nuances:

• The "inviting" system (where you had to use priority to invite a player to act) was removed from the core rules in the NA release version in October