Leveraging force multipliers, or, how to use mobs of mooks to take out those pesky player characters.
OpenD6 uses the Related Skills rules to allow characters to assist each other in skill checks, or to allow complimentary skills to boost each other. The process involves several dice checks and a bit of math, which can add drama in solving a puzzle but which only slows down the action in a combat. Essentially, complimentary skills or additional participants act as a force multiplier by adding half of the result points from an action as a bonus or penalty to the total of the main skill roll.
In the flow of combat, fewer die rolls means faster action. To streamline the process, every friendly combatant participating in the melee adds +2 to the attack skill and +2 to passive defense. The attack and defense may be increased by no more than +10. Removing opponents immediately reduces the bonus to their gang. Ganging up on an opponent provides a powerful but controllable advantage.
Steve is PC with Brawling: 5D and Passive Defense: 10. Three goons attack him, each with Brawling: 3D and Passive Defense: 10. Because they are ganging up on Steve, they can distract the focus of his attacks and help defend each other from Steve’s attacks. Each goon acts with Brawling: 3D+4 and Passive Defense: 14. In a one-on-one fight, Steve would have had a decisive advantage – the goons would only strike him half the time (mean attack roll = 11) and Steve would strike them 98% of the time! With the gang up bonus, a goon’s attack roll is boosted to a 95% hit chance, and Steve’s is reduced to 85%.
Ganging up only provides a bonus when multiple actors in the same location or acting against the same target provides an advantage in position, leverage, or timing. Each actor must be able to materially enhance the performance of the other actors simply by their presence. Melee combat allows all three advantages to be leveraged by a gang. Ranged combat allows none of these advantages because the gang cannot affect an individual shooter’s skill.
Social interactions may or may not allow actors to gang up on a single target. Aggressive actions such as intimidation attempts are almost certainly suitable to gang bonuses. Subjects of persuasion attempts are less likely to respond favorable to groups ganging up on them in an argument.
Any action that requires another actor to make a skill check in order to provide a bonus is not suitable for a gang up bonus. Technical skills and movement skills may benefit from instruction by using the Related Skills rules, but are not suited to gang bonuses.