The authors of this article seem to interpret this as an imaginative fancy of his that he "created"; rather, this actually seems to be a classic case of a polyfragmented DID system [of identities], also known as complex DID.
Oftentimes, alters are not formed consciously, and this is a severe disorder that is heavily traumagenic in nature. In my personal nonprofessional opinion, it's one of the harder non-neurodegenerative diseases to live with.
Source -- personal experience, I'm on the dissociative spectrum in some way, as best as I know. Expecting to receive a diagnosis shortly as an OSDD-1b system, and potentially DID under the ICD/ANP qualifications. The dissociative spectrum is actually shockingly common as a disorder, appearing in up to 1 in 12 in the general population, but is almost never diagnosed because much like PTSD in the 80's, it's heavily underemphasized and is seemingly not well-popularized in psychological circles today. Rather, the food fight over the legitimacy of DID seems to be taking away from work that could be done to further dissociative treatment modalities/other complex trauma disorders. Sauce on the 1 in 12 stat: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579511/
More info on polyfragmented systems here:https://this-is-not-dissociative.tumblr.com/post/18617448707...