I think this is the coat he wore in the Rampart Range video as well. It looks completely different than the Australian style dusters with the shoulder capes both Eric and Dylan wore. I've been looking myself, but I'm not finding anything with the basic keywords I can think of. Looking for this along with columbine search terms only describes it as a "leather trench coat".
If this thread is in the wrong section or if it shouldn't exist at all for whatever reason, feel free to do as you please with it mods.
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Deimos floats above hell itself!