If this is the case, I've been misunderstanding what the Defining Soul actually does. Before reading your post, I was thinking they were the closest thing to a Fetich a 3rd circle would have, in that they would define/exemplify why the 3rd circle is the way they are. So they're more like a representation of the 3rd circle demon's ability to redefine themselves? Trying to find more answers on the topic, I found this link talking about the soul types, I'm wondering how accurate it is: FrivYeti/TheDemonSouls - Exalted - Unofficial Wiki . Is the Expressive soul usually going to be the one that acts most in-line with the 3rd circle's themes, acting to express its nature?
I'll quote Games of Divinity here:
The demons of the Third Circle, like their superiors, have multiple souls. Typically, a Third Circle demon has seven, defining her ability to protect, gratify, define, communicate, express, reflect and understand her own essential nature. This is the second step in the demon hierarchy: Each one of these souls takes form as a demon of the Second Circle.
So, at least from this, I don't believe that there is any demon who specifically serves a fetich-like for the Second Circles. That's why, no, I do not agree with Friv Yeti. The Expressive Soul is the demon who forms from the soul that defines the capacity of the Third Circle to express themselves. Hence, they will have their themes along the lines of how the Third Circle expresses itself.
Ligier's Expressive soul is a crafter, who makes beautiful things from the fabric woven from the voices of others - who lose their voices. How does Ligier express himself? He crafts beautiful things from the flesh of his greater self, mutilating Malfeas to do so. But the Weaver of Voices has none of Ligier's arrogance nor of his contempt for Malfeas.
Hence, with the Defining Soul, it's defining the demon's capacity to define her own essential nature. And that, I feel, provides the more useful insight into Munaxes and Octavian. Octavian indicates that Munaxes defines herself by dominating others. She is a people who needs people to be her inferiors. As a... uh, bottomless chasm, she needs people to be... uh, falling into her? Or maybe she needs to subjugate other's terrain?
... shit, that's it. Huh. Yeah, I think I unravelled Borgstrom's "joke" with Munaxes. Of course her Defining Soul is a conqueror. She's a chasm, so as a chasm she's defined by the terrain around her. She needs to exist within a landscape, but for her to exist she has to expand and tear the land apart. And hence Octavian must expand and conquer endlessly, because he defines a hole in the ground, and a hole is defined by making itself be where other things were previously.
Mmm. That's intellectually satisfying.