I was talking the subject over with my sister via email last night.

Now she's of the opinion that it isn't impossible for Hal to have MPD/DID. We assume that his childhood was horrific. He was brought up in a brothel, he didn't know who his parents were. I can't imagine the situation in itself wasn't healthy, physically as well as emotionally. I could imagine that he suffered all kinds of abuse, that there was no maternal of familial nurturing of any kind. I could also imagine that this alone could help 'create' a psychopathic type personality (on this subject, i recommend you read 'The Psychopath Test by Jon Ronson, it is utterly fascinating) which i personally think would've attracted a vampire to recruit him. Some of those who suffer such horrific abuse quickly learn to decompartmentalise different aspects and they develop 'personalities' to help cope with such horrors, ie a dominant personality and a more subservient ones. In cases some who suffer this disorder have no knowledge of when for example a dominant personality steps in. It could explain Hal asking Crumb whether 'he' was here. Stressful situations could manifest it.

I would hope that we'd find out more about Hal's mindset and whether this would explain his good and bad cycles. After my arguing that i didn't think it was MPD/DID, the circumstances of his past could explain it but given we only have two more episodes, i doubt that we will.