Spirit Bone

Right after throwing the pieces of his arm into the forge, the first thing Ed did was ruminate through his mind. He wanted to find some sort of hint. Ed needed some insight on what exactly a drop item was. 

Was it his entire being condensed into a single material upon death? A physical manifestation of his consciousness that carried magical powers? Or was it nothing but an item made by the dungeon on a whim?

'Let's see… the items should reflect my current body or the characteristics it possesses' Ed chose to start with this. Although he had only seen the white bone once and couldn't say this for certain, he doubted the drop would have changed from then to now.

If it did, things were a bit troublesome since it could affect his progress moving forward but Ed couldn't think of a reason for it to change. He could only cling to this starting point and hope it wasn't leading him astray.