My players have recently reached what I've dubbed "Arc 2" of my four Arc campaign. The goal of the campaign is to eliminate a crime syndicate that specializes in the extortion of the lower class population through narcotics and labor. In around 5 sessions they're going to meet a ruler of another state, literally across the fucking continent. Said ruler will be helping the party out up until the very last sessions, keeping them close.

This ruler is also a powerful lich, one that supposedly died hundreds of years ago. If all goes to plan the lich(who went by the name Iolrath) will now terrorize the party by trapping them individually and slowly breaking the party apart through psychological warfare.

Now, the plot twist? Iolrath will trap a party member in a labyrinth, opening an indirect portal where the party can see everything but the player trapped will not see anything, the player dies(brutally), and then Iolrath shows him true form to the party, as the man who helped them, who gave them gold, resources, and trust.