I've always wondered why Typhon targeted the Blue-Green system as the Whorl's ultimate destination. (This assumes the ship did not end up there by accident or miscalculation.)
Speculation: could this be because he himself actually hails from Blue-Green? "Typhon," after all, is a mythic name, and according to Wolfe's nomenclatural stratagem, this should make him an alien--so perhaps his launching of the Whorl has merely been his way of returning home--one grandiose beyond all believing, and not simply as some expatriate, or even a legendary conqueror of various galactic realms, but as a god. Typhon has also previously told Severian that "I was not born as I am, or born at all, as you meant it," which to me implies a possible exogenetic origin; and both Typhon and the Neighbors bear doubled body parts (heads vs. limbs), so there's a relational twinship between the two. And what better army to finally eradicate the dreaded inhumi than one consisting of chems and taluses?
This might also explain the alliance between the Neighbors and the Mother (since it appears to be the former that supplies the magic ring Seawrack gives Horn). If she's truly Scylla, as I've proposed, they're not so much aiding and abetting an alien intruder (I refuse to call her a wetback), but one of their own native kin (if perhaps deracinated; there's evidence she's resumed her old sea monster form if we're to believe Seawrack's "She's another shape, very big" and "She doesn't look like a woman unless she makes part of herself a woman." OBW, 244).
Possibly, if we could just make out a Neighbor's facial features, this might provide a clue? (Or do the VP look like Horn?)
Robert Borski
*This is WHORL, for discussion of Gene Wolfe's Book of the Long Sun.