The Soul tag is currently of type "character". I would imagine that in this case the concept or entity of a soul would take precedence over a character named soul.
I did this because I was looking at the soul_vore tag, so I didn't immediately feel like it should simply be merged into Spirit.
I did a brief survey over the images currently tagged with soul and came up with evidence in favor of the majority of images referring to the concept of a soul.
So I request that Soul be turned into a normal tag type.
http://e621.net/post/show/99298 The concept
http://e621.net/post/show/84534 A character(?)
http://e621.net/post/show/62677 A character(?)
http://e621.net/post/show/48151 The concept
http://e621.net/post/show/21031 The concept
http://e621.net/post/show/105450 The concept
http://e621.net/post/show/112401 The concept
http://e621.net/post/show/114203 The concept... I think?
http://e621.net/post/show/118816 The concept
http://e621.net/post/show/131387 unsure. A Character?
http://e621.net/post/show/131392 A character or artist.
http://e621.net/post/show/187403 The concept
http://e621.net/post/show/225405 The concept
Updated by Rainbow Dash