Sharddinnerplate

My personal opinion is it is a shard blade covered in a white robe. It mumbles something back at hoid when he asks him something.

Nahel bonded Spren can appear as any shape as long as it is metal, technically they could become a nail right? Could you perform hemalurgy with a spren? Perhaps that would affect the bond and give the radiant allomancy/feruchemy??

What was the spear vin used to stab the lord ruler through the heart made out of? Where is that spear?