Niche D20This variant rule requires that every unit have a front, back, and sides and provides additional bonuses to an attacker for attacking a defender from the side or the rear. This replaces the normal rules for flanking, and creates a dynamic situation where positioning on the battlefield can be even more important.
When a creature takes any voluntary movement (whether this is from regular movement, a Shift, or a Run action) it declares its facing at the end of the movement. When a creature makes an attack roll, it automatically turns to face the target of the attack (placing the target into one of its front-facing spaces). A creature may, as a Reaction on its turn, change its facing.
Using a square grid, a creature that takes up 1 space will have 8 spaces bordering it: 3 front-facing spaces, 4 side spaces (2 on each side), and 1 rear space. A large sized-creature (which takes up 4 squares) would have 4 front-facing spaces, 6 side spaces (3 on each side), and 2 rear spaces. Larger creatures will have their facing spaces broken down in a similar way.
Using a hex grid, a creature that takes up 1 hex will have 6 spaces bordering it: 3 front-facing spaces, 2 side spaces (1 on each side), and 1 rear space. A large-sized creature (which takes up 3 hexes) will have different spaces of its facing based on whether it has 1 hex as its front side or 2 hexes as its front side. If the large creature is using 1 hex as its front side, it will have 4 front-facing spaces, 4 side-facing spaces (2 on each side), and 1 rear space. If the large creature is using 2 hexes as its front side, it will have 3 front-facing spaces, 4 side-facing spaces (2 on each side), and 2 rear spaces. Larger creatures will have their facing spaces broken down in a similar way.
When a creature is threatened from one of its side-facing spaces, the target gains the flanked condition. When a creature is threatened from one of its rear-facing spaces, the penalties from the flanked condition are doubled. Features that worsen the penalty imparted by the flanked condition (such as the Pack Fighter feat) provide their full bonus in rear-facing spaces and half their bonus in side-facing spaces. Additional effects and bonuses that apply when an opponent is flanked (such as the Sneak Attack class feature) do not activate from side-facing spaces; these effects only apply to attacks that originate from rear-facing spaces. Additionally, being behind a creature grants concealment from that creature.
If an attacker has a feature that impart the flanked condition when in a position other than normal flanking positions (such as the Barbarian’s Improved Chieftain savagery) that feature instead provides side-facing bonuses in front-facing spaces and rear-facing bonuses in side-facing spaces. If a creature cannot be flanked (such as from the Uncanny Dodge class feature, or the All-Around Vision universal ability) there is no advantage gained from being behind or to the side of that creature.