The Devoted Spirit Stance Iron Guard Glare reads:
While you are in this stance, any opponent that you threaten takes a -4 penalty on attack rolls against your allies. Tome of Blades p. 59
Let's consider a phalanx of Crusaders with normal melee weapons in the first line and reach weapons in the second line, all in Iron Guard Glare stance. Now an opponent is directly in front of the first line: He attacks the Crusader directly in front of him. He is threatened by the two Crusaders left and right of his target and three Crusaders in the second line, totalling 5, all glaring him down.
Does he get -20 on the attack roll or -4?