Secret of Phantoms' Cloister is an adventure module from the RPGA Legacy of the Green Regent campaign. It was never released to the public.
In the last adventure, the party entered the Mind of Karsus, where an unspoiled version of Phantoms' Cloister, called the Monastery of the Fallen One, exists. It is populated by the shades of monks who worshiped the momentary god but now desire only release from their extraplanar prison. Along the way, the party can rescue a relative of the High Lord of Loudwater, Nardine Twohands.
Secret of Phantoms' Cloister was never publicly released. Information about the content of the adventure is taken from other modules that were released.
LGR01 Extermination • LGR02 Gray Hunt • LGR03 Key to Phantoms' Cloister • LGR04 Secret of Phantoms' Cloister • LGR05 Dark Exodus • LGR06 Epidemic • LGR07 Nurture and Nature • LGR08 Rat's Bastard • LGR09 Denial of Resource • LGR10 Into the Fallen Lands • LGR11 Humility • LGR12 Tyranny • LGR13 Book Knowledge • LGR14 Native Intelligence • LGR15 Caravan to Waterdeep • LGR16 In Cold Blood • LGR17 Tour of Duty • LGR18 Feast of the Moon • LGR19 A Difference of Opinion • LGR20 The Howling of a Mighty Storm • LGR21 The Truth of Hearts • LGR22 As Seconds Slip Away • LGR23 Strange Bedfellows • LGR24 To Sever the Snake's Head