i had this crazy theory earlier on in the episodes, resulting from the fact that the child sprite of serena changes according to the hair colour to be one lyrra, kloe, cetsa that perhaps Rhue is, sort of like the purpose, a force of nature, or some sort of mythical character on the way - that is singlely driven by a love for a perhaps non-existent lost love, until he somehow loses his memory (there seem to be incidents when people mention something along these lines) then begins again, possibly under a different name (im sure it is mentioned some where, other than midian, where . I dont nessessarily believe this theory but I thought it might be nice to share it.
perhaps one of his earlier incarnations was the paraphalyn and thats why no one sees it - also Gaius appears to have hidden knowledge of Rhue, he reacts in a certain way, when strata beats Rhue in the estrana tournament - also thelin says way at the beginning of e1 "are you sure this is your first plunge?"