50 years... that's long enough for anything to kind of become 'just the way it is', huh. Who alive would even remember when it was different? It all happened up at that manor, far away.... and then 50 years of breathing in that 'soot'.
Speaking of the soot, how fiendish to make sure everyone arriving is dosed with it as soon as they enter... burning more of it in that place then anywhere else makes sure you start to feel the effects soon. Soot coffee makes you feel happy and loyal in a very intense direct way and clear your short term memory, so long term slow exposure just makes you cheerful and slightly more obedient?