Ok so i am going a bit crazy trying to figure out what color Alpha legion really is! So far i have the following.....
Novel's
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-Purple Armor
-Silver Trim
-Green Shoulder Icon
Horus Hersy, Collected Visions
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-Dark Blue Armor
-Silver Trim
-Green shoulder Icon
Art Work For Novels\Other things
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-Blueish purple armor
-Silver Trim
-Green Shoulder Icon
Forgeworld
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Metalic blue armor????
-Green Shoulder Icon
So at least we know they have Silver Trim & a Green Hydra..........