My initial guess was that it was left as a name card of the assassin. Did you have the same thought too?
As the story progressed, I began to think it could serve as a biological weapon. Apart from its hallucinogenic and trance-like effect, the flower may have hypnotic properties that cause the ‘sniffers’ to obey the commands of the perpetrator. Having said that, there must be an antidote to hinder such effects on the culprit him/herself. Yup, I was absorbed into that idea a lot.
I have to mention that this story gave The Village vibes as well with their elaborate, collaborative yet full of conspiracy plan. The difference is that the Jeongran Society wanted to rule the world instead of cooping in their own societal order. Turns out it’s a symbol of loyalty. Total subconjugance to the leader and the objective. Although I still have trouble understanding who the leader of the society is. Is it the mayoral candidate or is he just a puppet of his wife, who was not chosen unanimously because she’s a maniac? I mean who gets to make the decision that it is your time to die for The Cause?
Now that I know the significance of the blue orchid, I have to find out if this blue orchid is real after all.