Something else to consider; just because a horde's Magnitude is dropping it doesn't neccessarily mean that people are dying; the horde is simply becoming less of a tactical threat. As I ran Final Sanction I described Magnitude reduction in several different ways:
Abstraction is the key. That's how in our game a heavy bolter in one turn was able to inflict 18 Magnitude damage while firing 10 bolts. I love these types of rules because they have the potential to really bring out GM and player creativity. When you have rules designed to work a little more abstractly you have to watch trying to "pin-down" universal specifics such as "1 Magnitude always equals 12.5 enemies". Embrace the abstraction and allow your creativity to intrepret the things that happen as you go. You'll find your game becoming more engaging and vivid without wasting so much time with the minutia of rule specifics that don't neccessarily add anything to the game.
I totally agree with this as well, and the abstraction (and freedom thereof) made for some pretty dynamic and entertaining combat encounters.
The one issue I had as the GM, though, was figuring out how to describe numbers. Does a Magnitude 50 Rebel Horde represent tens of men? Hundreds of men? Not having any benchmarks whatsoever made it difficult to figure out how to consistently narrate enemy numbers to the players so they had some idea of varying difficulty. I don't need a hard and fast formula for Horde numbers, and I recognize and appreciate the flexibility of the abstraction, but having some vague benchmarks would definitely help.
...Especially since my group is looking at porting the Horde rules over into Rogue Trader, and we're trying to figure out how to buy Magnitudes of men for the RT's personal army
We were thinking the same thing for Rogue Trader. My thought was to base hordes on "units". Something like:
These are just some ideas, ultimately it doesn't matter. When the rogue trader goes to "acquire" a unit it will simply be a type (stat block) and a Magnitude.
For my game I'll just have the crew list their total Magnitude worth of any type of troop. How big any given horde will be is up to the PC's. For example lets say the crew has 200 Magnitude worth of conscripts aboard the ship. When they deploy they can have four 50 Magnitude hordes, two 100 Magnitude hordes, or any combo therein. Since the average rogue trader vessel may have 15,000 to 50,000 people aboard, does it really matter how many people are in the horde? Not in my game.
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@OP: As others have pointed out, it's going to vary wildly by factors such as troop type, cover, morale and ammunition stocks.
How often do you (or your GM's) do RF for NPCs and especially for adversaries? I only do it on boss-style characters, but never on regular guys.
I use RF for all major NPCs ("boss-style"). For big fights, I sometimes bring in a limited version of RF where lesser NPCs can pile on damage until they actually manage to wound a PC/major NPC. So no 100+ damage from one power sword hit for them.
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Danger in delay
Meaning we only need an approximate relationship between magnitude and the scale modifier to buy gear for a group.
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