Imagine the following situation:
A Warlock is in the zone with two enemies (a guarding creature on the ground and a flying creature). The Warlock has the Lash of Hellfire equipped and wants to attack the flying creature with the Reach Ability of the Weapon.
Two possibilities
-> first: A guard on the ground cannot prevent 2 flying units in the air from fighting. The Warlocks attack goes in the air. Although it is a melee attack, its target domain is not in the guards reach. The Warlock may attack the flying creature.
-> second: The guard redirects all melee attacks made in that zone onto itself, so the Warlock has to attack the guard and cannot attack the flying creature.
Whats the answer to this problem?