Frank Mentzer stood at the precipice of a design revolution in 1986 when he released the Dungeons & Dragons Immortals Rules, a boxed set that promised to take players beyond the mortal coil and into the realm of deities. This was not merely an expansion for high-level characters but a complete reimagining of the game's cosmology, transforming the humble adventurer into a being capable of shaping the multiverse itself. The publication marked the final chapter of the Basic Set series, a five-part collection that had evolved from the Basic Rules of 1983 through the Expert, Companion, and Master Rules. While previous sets focused on survival and conquest, the Immortals Rules introduced a system where experience points were exchanged for power points at a rate of ten thousand to one, fundamentally altering how characters grew and interacted with the world. The set contained two booklets, one fifty-two pages long and the other thirty-two pages, written by Mentzer and edited by Anne Gray McCready, with cover artwork by Larry Elmore and interior illustrations by Elmore and Jeff Easley. Harold Johnson also contributed to the editing and development process, ensuring the rules were tight enough to handle the immense power levels involved. The core concept was simple yet terrifyingly complex: characters who had transcended levels now competed in the Olympics to advance in rank, a mechanic that replaced the traditional leveling system with a political and competitive struggle for supremacy. This shift meant that the game was no longer about defeating monsters in a dungeon but about navigating a vast, interconnected multiverse where the stakes were the existence of entire planes of reality.
A Multiverse Unbound
The Immortals Rules expanded the D&D multiverse system to include an Astral Plane that permeated and connected the whole of the multiverse, creating a web of existence that stretched from the smallest to the largest possible dimensions. In this new cosmology, the Prime Material Plane was just one of many, surrounded by elemental planes, the Ethereal Planes, and a vast array of outer planes that ranged from mono-spatial atto-planes, which were about 1/3 inch big, to penta-spatial tera-planes, which were about 851 billion light-years big. The history of Immortals within the game told a story of cosmic origin, where once there were only three Immortals who discovered the multiverse and decided to give it order and purpose. These three entities set the stage for all future conflicts, establishing a hierarchy that the player characters would eventually inherit or challenge. The rules detailed the construction of personal home planes, allowing each Immortal to create a domain that reflected their will and power, a feature that gave players unprecedented creative control over their environment. The set also presented powerful new monsters, including demons that originally appeared in Eldritch Wizardry, and provided twenty-two pages of game statistics for these creatures to ensure that the Dungeon Master had the tools to challenge these god-like beings. The combat and magic systems were modified to account for Immortal powers, allowing characters to cast any magic spell and use new combat abilities that could reshape reality itself. This expansion of the game's scope meant that the traditional boundaries of the game were dissolved, replaced by a system where the only limit was the imagination of the players and the Dungeon Master.