two of my more extreme headmates are named Harmony and Elegy (or Ellie).
Harmony is the original here, and when she isn't just the composite of all of us, she tends to be the holder of all of our mood issues and hopelessness.
Ellie, by contrast, is essentially us when we go into "i am in emotional shutdown" mode; we used to called her "The Void" because she essentially is void of all feelings...on the surface.
the real secret here is that Harmony and Elegy are two sides of the same coin. they both feel the same strong emotions, but the real difference is merely how they respond to them. Harmony wants to sing it all out as loudly and unfiltered as possible. Elegy wants to hide it all in and silently sing a sad song solely for the self.
headmates are funny. sometimes the most different ones are more alike than any of them would ever wanna admit themselves.