Legit DID/pluralism/multiplicity has nothing to do with aping historical domain characters, interestingly; I think the "soulbonding" crowd (a whole different kettle of crazy that has nothing to do with DID) has aped the multiplicity terms from the psych domain and conflated the two. A friend of mine came out as multiple and I've read up on the subject -- controversial as the diagnosis may be and leaving aside questions of "oh it's all contagion," actual accounts and case studies say nothing about "I woke up one morning and realised I was also Alex the Great."