but do not forget: "who have total resistance 12 or more" is the cost.
And before you ask me for another Rule: Alle your Companions with a Signet have Resistance 6
AND all your Companions are Resistance -1 for each Burden your Ringbearer has.
exert 2
companions to make a (= one = singular!) minion (2x3=6) -6
exert 3
companions to make a (= one = singular!) minion (3x3=9) -9
exert 8
companions to make a (= one = singular!) minion (8x3=24) -24
and even if your skirmishing
Companion is a defender and fighting against x Minions, you only can reduce the strength of ONE Minion.