Magic is the lifeblood of many worlds. Yet in its raw form, magic is not an ordered force—it is the all-encompassing chaos of possibility. The same energies that can be shaped to create explosive fireballs, raise the dead, divine the future, heal the sick, and summon demons can do that and more without the direction of skilled spellcasters. Normally, this unfocused magical potential does not exist in reality; it lies beyond reality, where it waits to be tapped. Where exactly magic comes from remains a lively debate today, but when magic is unleashed without any attempt to focus it—when it leaks into the world in its raw form—the result is known as primal magic.
In some realms, magic is left to indulge in its raw chaos as it wishes—here, primal magic is often called “wild magic.” On the Material Plane, the world feels the touch of primal magic when the laws of reality themselves have been damaged. Here, magic flows in unpredictable tides and currents. At one moment, a region function normally while at another, magic won’t function at all. Usually, though, primal magic holds sway.
Manifestations of primal magic tend to build up potential before they explode into existence. Just as a thunderstorm doesn’t constantly lance the ground below with a constant beam of lightning, these bolts manifest periodically and almost randomly. And just as lightning can be called with lightning rods, primal magic can be purposefully or accidentally drawn out by utilizing magic in areas where such energies are building.
When primal magic manifests, roll on Table: Sample Primal Magic Events to determine what occurs.
As the primal magic exerts its power, consider crossing off the effect that occurs and designing replacement events and effects. If you want primal magic to play a big role in your campaign, you should try to ensure that no two effects are ever quite the same. One easy way to achieve this is to simply substitute random spell effects with unusual descriptions in place of normal ones, such as a black fireball that smells of roses and deals acid damage.
Spontaneous primal magic effects can occur as often or as infrequently as you wish, but as a general rule, try to limit the effects to one per combat encounter at most. The majority of primal magic effects should instead occur when creatures activate magic items, use spell-like abilities, or cast spells in such an area (simply carrying a magic item or gaining the benefits of a constant-use item or spell effect isn’t enough—it’s the actual act of activation or casting that triggers primal magic). When a creature activates a magic item, casts a spell, or uses a spell-like ability in an area infused with primal magic, there’s a 50% chance that the spell effect is replaced by a primal magic effect. A spellcaster casting a spell, using a spell-like ability, or activating a spell completion or spell trigger magic item can make a concentration check (DC = 15 + twice the spell’s level) to focus the magic and avoid triggering a primal magic effect. Creatures activating other kinds of magic items do not have the option of making a Spellcraft check to avoid triggering a primal magic effect.
When a primal magic effect occurs naturally, it targets a random creature or location in the vicinity around the PCs or whatever region you wish to inflict the event upon. When the effect occurs, you need to determine the CR of the event. If the event is triggered by a spellcaster or a magic item, the event’s CR is equal to the spellcaster’s or item’s caster level. When an event occurs naturally, you can roll 1d20 to determine the CR. Of course, you should strongly consider lowering primal magic event CRs to match or at least closely approximate the average party level of your PCs. Not all primal magic events are harmful, but it’s neither fun nor fair for players to frequently be hit with an effect that’s too far beyond their ability to deal with.
In Table: Sample Primal Magic Events, “CR” is used to indicate a mathematical value; use the primal magic’s CR to set this number. For example, a CR 11 primal magic event that lasts for “CR minutes and affects an area with a radius of CR × 5 feet” lasts for 11 minutes and affects an area with a radius of 55 feet.
Areas affected by primal magic are like scars upon the rugged flesh of the world, invisibly and intangibly overlaid on the fabric of reality. Generally, areas of primal magic form in places afflicted by forces beyond mortal control—areas scoured by godly wrath, breaches between the planes, sites where powerful artifacts were destroyed. In most of these instances, the primal magic subsides as reality repairs itself, though it might take a matter of weeks, years, or even centuries. In the cases of extreme abuse, an area’s magical cohesiveness might never recover, resulting in areas of permanent primal magic. In general, the location of existing areas of primal magic and the creation of new areas is left up to the GM, but should always be the result of magic of extraordinary force or of an arcane catastrophe of epic proportions. Such should be encountered only rarely, allowing such sites to retain their sense of danger and calamitous history.