One thing I keep trying to wrap my head around is how cherubs have a culture and civilisation at all when adult cherubs are solitary deep-space wanderers who only meet to fight and mate. Calliope and Caliborn are probably not having a normal cherub childhood. So perhaps there are teeming cherub nursery-worlds full of gregarious young cherubs? That would make for an interesting setting, where everyone you meet is two personalities in one body.