Please, tell us what happened!
The group consists of an Elven Hexblade Warlock/Shadow Sorcerer, a Fire Genasi Diviner Wizard, a Tabaxi Scout Rogue, a dwarven Ranger/Forge Cleric, an Aasimar Light cleric, and a human Grave cleric. All of them are sixth level. The group has gone through each of the various shrines within Omu, tracked down the red wizards who beat them to two of the puzzle cubes and defeated them, then descended into the Fane of the Night Serpent to chase down the final one.
They spend the first day probing into the secret entrance to the Fane, killing off the Yuan-Ti guarding the entrance and then defeating the brood keepers and the slaver in the southern portion of the dungeon. Then, they used Water Walk to move across the river, encountering the Hydra and handily defeating it. The group decides to call it a day, gather the drugged slaves they found, and return to their base camp in Omu (the group rescued all of the sailors who were in the wreck of the Sea Goddess, rescued Orvex from the Red Wizard Camp, and also convinced one of the mercenaries working for the Red Wizards to join them after wiping out the rest of the mercenary crew). I rolled secretly to see when the temple would discover the group's incursion and then started rolling for reinforcements.
On the second day, the group again used Water Walk on the river (damned Clerics and their rituals) and found the main throne room. There, they find Ras Nsi and his crew. Ras Nsi tries to convince the party to work for him, promising them the last puzzle cube if they do. The group wants nothing to do with it and attack.
The wizard throws a fireball. Ras Nsi recognizes this and tries to counterspell...which is then counterspelled by the Wizard. Meanwhile, Ras Nsi's bodyguard rushes the Dwarf and the Hexblade. The Hexblade soon falls (Sekelok deals some crazy damage!), and the dwarf is doing everything he can to survive. The Light cleric throws a fireball, taking out a few more of the Brood Guards, and the Grave Cleric rushes to heal the Hexblade (Grave clerics are really good healers). Ras Nsi decides to withdraw to his lair for his magical shields while the rest of his guards delay the party. The Tabaxi Rogue sets himself up to target Sekelok, and the grave cleric uses her channel divinity to inflict vulnerability to the rogue's incoming sneak attack.
Needless to say, the entire encounter took 10 full rounds...the wizard and the grave cleric both dropped once, and the warlock came very close to dying twice (once due to massive damage, and once due to rolling a 1 on his death save after being taken down by one of Ras Nsi's fireballs). Spells were flying left and right, and the party (even though they were completely fresh coming into the encounter) were almost completely out of spells.
