Our group cannot agree on this!How can your group not agree on this when it's in the rulebook (p.5):
If you are counting tiles, you never count diagonally;Granted, that's talking about Diagonal Movement", but the same counts for targeting (p.9)
When you decide to attack, first determine which Monsters your Hero can target. A power specifies what Monsters you can target, ranging from only Monsters in an adjacent square to a Monster as far as 2 tiles away.
Remember the difference between squares and tiles when making attacks (see page 5).
Most important, keep in mind that you can never trace a diagonal path between tiles. If a power lets you attack a Monster within 1 tile of your Hero, that does not include Monsters on a Dungeon tile that is diagonal to your Hero’s tile. You also cannot attack a Monster within 1 tile of your Hero if a wall completely blocks the path between the Hero’s tile and the Monster’s tile.