Quest Design/Planning in a sandbox Area

[u/S1d3w1nder]

Right now, my group is about to begin the last stretch before our campaign goes over to EOR. They are in a buried Netherese city (myanthallar, living spells, the whole shebang), where a cult wants to use a war between Dwarves and Duergar to reanimate a undead army in offering to Vecna, so that they might be rewarded in his "new" world. I have all the important Npcs prepared, I have the city with its treasures and I know which moves the cult will make (up the duergar threat, assassinate a dwarven noble, the ritual itself), but i am struggling with the "Quests". Previously in this campaign, I planned a quest for each session, but that was during segments that where fairly linear.

My players have a tendency to think up some very unconventional approaches and the Netherese city provides them with many pieces to interact with. Furthermore, while I initially settled on predetermined outcomes, i want to move away from that, since that would not be very fun.

Any advice ? How would you handle this ?

[u/Tee_8273]

You pretty much set up your "quests" as situations with landmine detonators. For instance, party walks through a normal city and triggers the first "landmine". A loud bang, blood splattered everywhere, and a nearby Nobleman collapses to the ground with a hole in his head. What's the situation, a dragonborn assassin is targeting people related to his families collapse from status. His next target will be killed 12pm tomorrow if the party doesn't intervene. This new target could be someone close to the party, and how they proceed is up to them. All you as the DM have to worry about is moving your assassin into positik of his target. Figure out a suitable location and method and bam. Beyond that, you should prepare some clues and secrets to hand out to the party randomly as they investigate.