I started by looking at the form of government my magical world was going to have. The Fairy Queen and her Council are loosely based on the kind of arrangement Queen Elizabeth Tudor would have had and L'Evallier is roughly the equivalent of William, Lord Burghley.
The Queen is aware she needs L'Evallier to be a kind of public conscience. He sees it as his duty to keep her to account. This role has become more important since Eileen defected. Eileen admires L'Evallier's honesty and courage but resents the Queen for not listening to her complaints. The Council gave me a means of causing Eileen more trouble as it was their role to hold her to account to and the fact that she does not abide by rules, argues at times when it would be more sensible to be conciliatory and can be her own worst enemy gives the Council plenty of ammunition to use against her. The Council also gave me a means of giving the Fairy Queen grief as they can put pressure on her to take action against Eileen and/or the Witch. And it means if the Fairy Queen wants to get the Council off her own back, it means she will sacrifice someone else to them. All of this gives lots of scope for rivalries (and between individual members of the Council too) and ensures the Queen and Eileen, while still living in the Kingdom, have people that pressurize them. L'Evallier especially feels this is only just given the royals ought to be accountable.