The barriers giving rise to Abyss take the form of mild dissociative amnesia. I have incomplete memory sharing with my headmates. This is what keeps them distinct from me, and protects me from the bad things they know.

I have no concrete factual recall of my trauma, and the only way I know what happened at all is because of nightmares, aftermath, what they've told me happened to them, and very sparse (but extant) objective evidence.

I do not have very severe daily-life inter-alter amnesia. I have what are sometimes called “grayouts” rather than blackouts: I dissociate, switch, and lose time, but the switches are gradual enough that most of what I need to remember to function has time to carry over. Rather than blacking out and waking up as someone else, I just get really intense mood swings, that also temporarily change my opinions, values, priorities, internal gender identity, felt sense of age, ideal body image, favorite color, and some of what I'm easily able to remember about my life and current situation without needing to actively remind myself. The only way I was even able to figure out for sure that I switch at all is because I'm constantly getting intrusive thoughts that sound like other people talking to me and which side of the conversation is under my voluntary control keeps suddenly changing every so often.

My everyday-life amnesia used to be slightly more severe. As a child, I was always forgetting everything ever told to me, forgetting every task I was ever assigned, forgetting every face and voice and name I knew, and losing everything I ever took out of the house. There were a few times I did actually completely black out and wake up to discover I'd done something uncharacteristic. But these more severe symptoms cleared up as I grew up.

My headmates have their own distinct thoughts and feelings that occur in parallel to mine but are mostly inaccessible to me. I have absolutely no idea what they're thinking or feeling at any given moment, unless either they voluntarily tell me, or I involuntarily switch to them.