Nightmare Scythe -> Blade: Rin = transfixion/light
Nightmare Scythe -> Blade: To = detonation/wind (reverse the order for gravation/dark-earth)
(Note: Nightmare Scythe just blinds mobs, does no damage, so we'd be losing a little by using it.)
Shadow of Death -> Blade: Teki = fragmentation (I think this is the one we stumbled over?)
(Plus others, those are just a few quick ones I saw.)
I'm not sure what the letters after the WS name mean...
Edit: Oh, and my skillcap on marksmanship at my current level is 109. So I'm like 45 levels under it... I wonder if there's a chance in heck of hitting our XP mobs with that much of a difference. (I need to find -- or put together! -- a skill-up party.)