15th september

Killer Queen is the powerful mastermind of Globalsoft, who Khashoggi works for/with to ensure all live music and instruments are banned. The villain of the plot, hence her accurate title. her reign of terror makes sure everyone is kept in line, or they are brainwashed.
khashoggi is the

head of the secret police, and devoted to stand by the queen's side. he is described as "heartless" and cold as he initially never was brainwashed when he chose to stand with the boss.

Killer queen's role's effect and contribution to the plot is that she represents a leader with too much power, creating their own rules and forcing a way of life on everyone under her, and any deviation from the social norm would be punished.
Khashoggi's contribution is that his character transitions into a weaker version, and as a result of Galileo and Scaramouche escaping the heartbreak hotel,  the queen turns on him and he gets brainwashed, becoming just like the gaga kids etc.

Killer Queen and Khashoggi's relationship together was strong and a sort of partner-in-crime connection. This however fizzled when the incident happened, which is interesting to see how quick she cuts him off like there was no real friendship etc. The queen stands by herself. Relationships with the yuppies can be seen as similar. The yuppies are infatuated by her and obey her commands which is clearly from the brainwash. I feel the queen sees them nothing more than her minions that carry out her orders while she watches over. The bohemians are the seekers of rebellion against the queen, bringing her and her minions down, which is the same feelings she has against them, to end their fight and create a few more gaga kids and yuppies and continue her leadership over planet mall.
Khashoggi's relationship is only significantly obvious with the queen and the secret police. His relationships mimic those of her's when exploring the bohemians, yuppies etc.