D&D 5E BBEG Greyhawk Vallahan Session Setup

[Jaiken]

Hello everyone. My players have finally learned about the villain of my Campaign.

Greyhawk is an evil politician that uses his fame, wealth and charlatan ways to manipulate the people and turn citizens and townsfolk against his enemies.

I need help building traps for the players to face off. Here are the players characters:

Half Orc Vengeance Paladin Level 9

Hill Dwarf Moon Druid Level 9

Dragonborn Reborn Custom class Magus made by Benjamin Huffman Arcane Order Level 9 with a Spellcaster Sidekick.

Pompup (custom dog race that works like a Goblin) Valor Bard Level 9

Variant Human with Great Weapon Master Feat Storm Herald Barbarian Level 9 with Wall of Stone Magic Ring.

My main question is: What type of traps should I put in Greyhawk’s Castle? The castle is 3 floors high and has Ballista cannons that fire automatically.

The Session starts at Christmas time.

 

[aco175]

I always liked stairwells that become slides and dump people in cages. This way it splits up the party and forces the PCs to spend resources to escape cages. It is a bit harder to DM with split parties and each running into problems.