Attacking is one of the main ways you deal damage to your opponent's units and sites, and is a core part of Sorcery. Units attack as part of the Move and Attack basic ability. Certain rare effects may also explicitly allow attacks, e.g. Crave Golem. You may only attack enemy units or the surface of enemy sites that are at your location. When you attack, follow this sequence: Declare the attack target and check that it's a legal target right now. If not, end this process and no attack happened. Assuming the attack target is legal, 'attack' triggers are now satisfied and the defender has been targeted and attacked (e.g. Captain Baldassare, Sir Kay, Dodge Roll, Wills-o'-the-Wisp). Resolve those, using the storyline rules as usual for simultaneous triggers. Open the defend window. One unit may use the Defend ability, resolving its movement, if any. If it now occupies the attack's location, it joins the attack as a defender. If the original target was a site, it's removed from the attack. If the original target was a unit, it may remain in the fight or not, as the defending player chooses. Note that the defender is not 'attacked' nor 'targeted.' The opportunity to use 'attack' triggers (e.g. Dodge Roll, Wills-o'-the-Wisp, etc.) has already passed. Repeat 3.a and 3.b as many times as defending player wants, one defender at a time. Defend window is closed. Check for attack target legality again. Units that used the Defend ability are automatically legal targets (e.g. a Stealth minion chooses to defend, a unit on Dome of Osiros chooses to defend, etc.) Resolve the fight. If there are no other units involved since you're attacking an undefended site, simply strike the site, damaging it and causing the controlling avatar to lose that amount of life. The attack is over. Any 'after attack' triggers resolve now.