Anyone can say whether one card is going to be used, but if there is conflict, such as
"ARTHANASIOS:
SoFo"
"dawntodusk:
Arsenic
(dagger or whatever)
(shield)"
then we'll need to stop right there. It shouldn't matter who says it, but there must be an agreement by the team.
If you can get the point across, like So(...) for Shard of (...) then we'd understand, like arsen or vagger for arsenic and vampire dagger respectively.
If I'm unclear, you can ask again for more clarification.