Heroic adventures are annoying to solo with the stupid nightfall modifiers, and they're only on Mercury for some dumbass reason. PvP isn't even an option, because of how bad it is. Doing hundreds of strikes is the only other way to get them. This isn't FUN.
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100 strikes should get you every prophecy weapon. I have all available and im 25 strikes and maybe 15 cruc matches not that bad honestly.