Two NPCs, One Buried Truth

You want two characters bound by a secret the players haven't spotted yet. This gives you the shared truth and how each one privately remembers it, how each behaves when the other comes up, what each would sacrifice to keep it buried, and the one scene most likely to drag it into the open. Built for a slow reveal that pays off.

I want to design two NPCs who share a secret that predates the campaign. The players do not know yet that these two characters are connected. Give me: the shared secret and how each NPC privately remembers it, how each one behaves when the other is mentioned or present, one thing each would sacrifice to keep it buried, and the single scenario most likely to force it into the open. First NPC name and current role: {NPC_ONE}. Second NPC name and current role: {NPC_TWO}. Rough nature of the shared history: {SHARED_HISTORY}. How central you want this to become to the main plot: {PLOT_CENTRALITY}.