The idea was born from the following: Noise in Steven Eriksons Malazan world, Power sensitivity in many RPs. Uncontrolled rifts share similarities with the concept of wild magic in D&D.
In my setting mages tap into the 6 basic elements; fire, water, air and earth element and black and white essence. The first four are self explanatory, but the latter two requires more detail. The white essence is the life giving element. It is the source of growth and fertility. The black element is its opposite, the very source of decay, death and destruction. The elements can be woven together to create mixed spells (Flaming undead, etc)
All mages are born under certain stellar configurations. Their star signs decide which element they have a connection to (they can freely choose among the constellations).
The further away from his element a mage gets, the harder it is for him to cast spells. Thus a white mage (channels from white essence) will have a hard time to channel from black essence (will cost more magic points / mana).
If the mage fumbles or get a 'marginal success', the channelling may have created a small rift and a leak occurs. This rift can be trivial or very dangerous based on die rolls. In addition the casting of spells creates noise that can be detected by sensitive creatures.
Noise:-Whenever a spell is cast, it creates a controlled channel to the elemental pocket/plane/source, a rift of sorts, to the appropriate element. This rift disturbs the natural order of things and creatures connected to the element may notice. The chance of detection will increase with the potency of the spell. It is seldom indeed that normal spells attract attention. Some unlucky individuals are unsuited to the weaving of magic and have a higher chance of creating noise.
In areas connected strongly to a certain element the chance of detection is less when using spells of that element and higher when using opposing elements.
Clavius had done it again. His simple spell of masking, aimed at concealing the squad from the enemy, had created so much noise it actually attracted attention. It was evident everywhere. The corpse maggots poured from the week dead body of a centurion. They eased through the cracks of his armour, poured through his wounds. Their white bodies contorted in involuntary response to the casting before they tumbled and fell to the ground. Rats were pouring through the walls, screeching and clawing towards Clavius, while the ravens circled in the sky, spiralling ever downwards.
Every warlock and witch with power sensitivity and every restless spirit would have felt the tremors, and within nightfall they might expect spirits and familiars descending upon this location. Ordinary people felt nothing, of course, but at the local farmsteads the farm animals would act strangely, and the peasants would mumble about bad omens and make warding signs against evil.
The spell of masking still worked though, and Clavius Thuul ordered his men to make haste. The enemy was still out there, but was not likely to have sensed anything, so the fifth squad half ran towards the forest, desperate to get away before the animals made the enemy investigate.
Uncontrolled Rift:
-When mages fumble or succeed marginally an uncontrolled rift is created. The effect of this rift is determined by a die roll with marginal successes less likely to create a rift of any potency, most likely none at all. The rift will be related to the element tapped. If several elements are tapped simultaneously the effects should be custom made to reflect that (i.e. Fire & Water = Steam, Fire & Earth = Magma, Fire & Black essence = Brutal and devastating Smouldering flames, Fire & White = Dancing Fire globes that give of pleasant warmth, etc). The rift might only last seconds or it might (not often) last years. All rifts heal with time and the natural order is restored.
Some proposed effects:
(Ranges from the least to greatest potency)
White:
-A new kind of plant has been created. It grows right beneath the rift.
-A healing wind blows from the rift.
-Seeds of life begin to grow within all females in the area, whether they are eligible or not (even old women get pregnant)
-The recently dead are raised
-The white essence element merges with the surroundings. Everything grows at a supernatural rate and aging beyond maturity does not occur. The area will soon become a dense jungle where feeding is not necessary and fertility guaranteed.
Black:
-A hot wind blows through the rift. It has the vile stench of rot and decay.
-Local plants withers. The area becomes barren, shunned by animals, for as long the rift exists.
-A sinister fog rolls out of the rift and envelopes everything. All the nature as well as buildings and living beings are aged. (Buildings decay, trees grow, mountains erode and men age)
-The Black essence element merges with the surroundings. Life is snuffed out of everyone and everything within the area, leaving only dried corpses and dead trees.
Fire:
-Sulphurous smoke pours out of the rift
-Various degrees of flames leaking through (From small candlelight sized flame to full firestorm)
-Entities from the element of fire pour through the rift.
-The fire element merges with the surroundings. The ground slowly turns to magma, the plants and forest burn and fountains of lava spurt into the air.
Water:
-A small stream gushes forth through the rift (possibility of fish and other sea animals).
-Snow is sprayed in every direction from the rift. It is like a miniature avalanche coating everything with a fine layer of powdery snow.
-The rift develops a local geyser which spurts forth from the base of the rift.
-The element of water merges with the area. A new swamp with rivers and lakes evolve and might take long to dry out.
Earth:
-The rift causes an insignificant tremor. Small rocks will slide and birds will fly away startled.
-Sand pours through the rift, flooding the area. The ground gets covered by an inch of sand
- The rift causes disturbances in the very earth. An earthquake makes the earth shake and rumble, the earth opens wide and buildings collapse.
-The element of earth merges with the surroundings. The ground explodes as small volcanoes erupt and magma streams throughout the area. Soon everything is buried beneath tons upon tons of volcanic stone.
Air:
-Dust devils are caused by the rift
-Varying degrees of wind is created by the rift.
-The sky darkens and thunder booms as the rift cause a severe thunderstorm
-The air element merges with the surroundings and the area becomes a pandemonium of howling winds and whipping rain. Soon only the sturdiest of buildings remain and the area is abandoned by everyone.
Clavius Thuul prepared his spell. The greater incantation of summoning would call to the elemental lords of water and bind them to his service. He rolled up his sleeves and buttoned his robe. He cleared his throat and prepared mentally. The scroll of Tharus spoke of the dangers a mage faced when casting the spell. As he spoke the syllables with slow deliberation, his hands moved with trained efficiency. His mind raced while he wove the spell. How was that last syllable pronounced again?
As Clavius finished his spell, there was a bursting sound. Like a pipe springing a leak. Suddenly water gushed forth and he was nearly drowned before he managed to stand up and get his head out of the water. Behind him he could hear his men dying of laughter. Clavius had created yet another tale to be told by the campfire.
I have not incorporated this fully in my setting.
If you have any ideas or hints please post them here.
Feedback wouldn't hurt either.