Faction -> Damage They Use -> Damage You Should Use

Amarr -> EM, Thermal -> Thermal
Angel -> Omni (Primary: Explosive, Kinetic) -> Explosive
Blood Raider -> EM, Thermal -> EM
Caldari -> Kinetic, Thermal -> Kinetic
Gallente -> Kinetic, Thermal -> Thermal
Guristas -> Kinetic, Thermal -> Kinetic
Mercenary -> Omni (Primary: EM, Thermal) -> Thermal
Minmatar -> Omni -> Thermal
Mordus -> Kinetic, Thermal -> Kinetic
Rogue Drones -> Omni (Primary: Explosive, Kinetic) -> EM
Sanshas -> EM, Thermal -> EM
Serpentis -> Thermal, Kinetic -> Kinetic
The Seven -> Omni -> Kinetic
-Stacking penalties
1st = 100%, 2nd = 87%, 3rd = 57%, 4th = 28%, 5th = 10%, 6th = 3%, 7th = 1%, 8th = 0.1%