Rules Index | GM Screen | Player's Guide


Player Core / Chapter 8: Playing the Game / Movement

Flanking

Source Player Core pg. 425 2.0
When you and an ally are flanking a foe, it has a harder time defending against you. A creature is off-guard (taking a –2 circumstance penalty to AC) to melee attacks from creatures that are flanking it.

To flank a foe, you and your ally must be on opposite sides of the creature. A line drawn between the center of your space and the center of your ally's space must pass through opposite sides or opposite corners of the foe's space. Additionally, both you and the ally have to be able to act, you must be wielding melee weapons or be able to make an unarmed attack, you can't be under any effects that prevent you from attacking, and you must both have the enemy within reach. If you are wielding a reach weapon, you use your reach with that weapon for this purpose.

3D Flanking

Source Player Core pg. 425 2.0
Though battle grids are often two-dimensional, the game world isn't! Sometimes you might need to visualize a creature's space as a cube for flanking. For instance, if Valeros is underneath a flying sphinx while Lini is flying above the sphinx, they might be flanking it even if they're piled in an odd stack on your battle grid. And if Valeros were mounted on a horse, he might be able to measure from farther off the ground than normal.

In these cases, it's usually best to have the GM make the call on who's flanking rather than trying to do meticulous measurements in three dimensions.