If an enemy must move, it first determines a destination hex to move toward. The destination must be the closest hex where at least 1 targetable unit would be within that enemy’s range and in sight. To be an eligible destination hex, each hex between the enemy and its destination must be unoccupied. After the enemy determines its destination hex, it moves along those hexes. It moves even if it cannot reach the destination hex with its movement this turn.
When the enemy moves, it ends its movement immediately after it moves into its destination hex—even if it could move additional hexes to put more units in range.
If there are multiple destination hexes possible (or if there is no valid destination hex available), the enemy instead moves toward the closest opposing unit, even if it is untargetable. If there are multiple closest units, the enemy moves toward its priority unit. If there is a tie between priority units, the party decides.