Into that Darkness Peering: A Tale of the Lonely Coast
Initiative determines the order of creatures’ turns in combat. However, instead of rolling once per combat for initiative as stated in the PHB, we roll for initiative every round. Each player must make a Dexterity check to determine their place in the initiative order. The DM makes one roll for an entire group of identical creatures, so each member of the group acts at the same time. The DM ranks the combatants in order from the one with the highest Dexterity check total to the one with the lowest. This is the order (called the initiative order) in which they act during each round. Ties mean that those actions all occur at the same time.
Spells must be declared BEFORE the initiative roll. A spell caster who is struck before casting his spell will have his or her spell ruined. A tie does not ruin a spell.