I assume it's because he holds the trauma, like he's its personification, but there are many other personalities, and I doubt they're all gloomy. Maybe because he's responsible? (protective toward Mariane) or maybe bc he is self-aware, since he has access to the outside world? I'm not sure, one chapter isn't enough perhaps.
anyway, my question would be: Why is Mariane considered the original if the original identity was fragmented into pieces? Couldn’t she just be another alter who happens to be central?
I'm shocked you actually read my thing, I thought this thread was random answers to random questions, but I'm very happy !
That's a thing that happens in DID. For a clear analogy, imagine a glass of water. The glass is the amount of trauma your brain can handle, the water inside is the trauma. If you are well adjusted, with a good support system and you have developped emotional maturity, the glass gets bigger, so even if you receive trauma, it won't fill up as quickly and you can manage to empty it little by little so that it never overflows. Now, imagine that a child, who's glass is still very small, and has no way to empty it because it doesn't have emotional maturity or a support system, sustains an amount of trauma that immediately overflows the glass, what happens ? Either the brain breaks, or it tries to save itself by creating another glass, that's DID.
The other glass is basically another person, another personality, that can also hold trauma (in this case, it's Thomas). It doesn't mean that the original glass disappears, it's still there. Maybe most of the water has transfered to the second glass, and this one is a paper cup so it's opaque and Mariane can't see what it holds (she has no memory of the trauma Thomas has taken on), but she is still there.
But yes, it does happen sometimes that the original identity disappears, because the alters in a system aren't fixed, they can change, disappear, merge, etc... But in the story, Mariane is still here.
Why writer's block ? :c