Board Thread:General Discussion/@comment-26123021-20160211121249/@comment-26123021-20160214120649

Soul type is "boss monster". I don't think it was ever stated which soul has more DT. But boss monsters are represented by white with, as far as we have seen, a single red accent. But it would make sense, as a metaphor, since boss monsters have a white soul that contains DT but only a small amount. So white with a colored accent, and since we are most accustomed to seeing red souls as human souls- with two different red souled humans who are far more major characters than any other human- that would make the most sense as to the color used. Plus those are the actual colors of the accented objects, probably. We don't see enough detail to see Toriel's eye color in the overworld and I don't think Asgore brings out his trident in any other situation but they definitely aren't absolutely impossible colors.