Weird headcanon. I imagine them as siblings. A vindictive, overly controlling, narcissistic older sister, and two younger brother who resent her. Pharynx gets into fights with her but is kept around because he is actually useful, and Thorax took on the brunt of her attacks when Pharynx wasn’t around.

Why sister and not mother or some random Changeling Queen?

Because I can not follow norms in the slightest :D