Combats are the most complex events in the game, especially when multiple enemies are involved. It would not be fair to let a player handle it by himself when learning the game. Also, someone should look out for the enemy during combat - it is easy for a player to overlook a special ability.
If a combat happens, the player that was playing before the active player (or the player who knows the game best) should become the Combat manager. He makes no decisions for the enemies; it is just his duty to see that everything goes according to the rules. …