This world is fair, ruthlessly so. For every laughter, a tear is shed; all joy with equal sorrow is met. Remember this well, when reality bends to your will. Remember this well, when fate seems to strike you down.

- Opening words of First Principles of Magic, by Elisaveta

The law of equivalence permeates all aspects of this world - for everything gained, something must be paid. It can be seen in the prosperous cities, balanced by hostile expanses; the weak minds of monsters, balanced by strong bodies; the grand achievements of kings, balanced by all their depravities.
There are some in this world that come to know, to understand this law. To recognise equivalence is to be able to manipulate it, so such people are capable of miracles and catastrophes beyond imagination. Such people are called mages. However, this recognition does not merely take the form of knowledge, but instead experience, imprinted onto the soul through a Rapture/Rupture. Such an experience, which awakens an understanding of the world, is called Rapture by the more optimistic, and Rupture by those less so inclined.

All magic is based on the same principle of equivalence. That means that each act of Spell-casting will require a target outcome, as well as a sacrifice. In the game, Spells will be a vital tool to interact with the environment, defeat enemies and much more. Players will be given a great amount of freedom in what they want their Spells to do, but should take heed that the costs of those Spells will be partly up to GMs to decide.

Inevitably, some hostility will arise between players and NPCs (or even other players), whether that be a difference in opinion, a decade-long vendetta or conflict over some precious items. This is a completely normal phenomena, and even encouraged. After all, what's the worst that could happen to you? In order to resolve such hostilities you may have to engage in player versus environment (PvE) or player versus player (PvP) activity.
In order to determine who 'wins' in these conflicts and what exactly the final outcome is, GMs will take into account what Quirks a player has, how they have used their Spells and, most importantly, what exactly they are trying to do. As such, it is more favourable for players to try creative plans in place of purely relying on their character's capabilities. Nonetheless, regardless of plans, abilities and outcomes, the GM team will try to ensure that win or lose, players have fun engaging with the world and its inhabitants.

… The reason why so many mages pursue knowledge, even to the point of endangering their lives, is not merely obsession. As one comes to better comprehend the principle of equivalence, one will better be able to manipulate it. From enhancing aspects of yourself, to manifesting objects to bending reality to your will - there is no limit to what magic can achieve so long as you can understand how to wield it.

- An extract from one of Almustanir's lectures

Proof of your knowledge of equivalence.

Effect

• Temporarily enhance a capability of your character¹⁾

AND

• Temporarily diminish a capability of your character chosen by a GM (players will be informed of the diminishment)²⁾

Usage

• This Spell can be used once in each Uptime AND once in each Downtime
  
• The effects of this Spell last for 20 minutes

How is it learned?

• This is the first Spell that all mages learn, the most basic of manifestations of equivalence that appears after a mage's Rapture/Rupture. All players start the game with the ability to use this Spell.

Examples

• A mage enhances their toughness, making their skin harden and become like scales. This comes at the cost of temporarily diminishing their agility, making them into a shield - resilient, but practically immobile.
• A mage enhances their diplomatic ability, making their words attain a particularly enrapturing quality. This comes at the cost of their perceptiveness, making them easily able to resolve conflicts, yet unable to spot them in the first place.
• A mage enhances their pickpocketing ability, making their movement so light, delicate, and precise it is almost impossible to detect. This comes at the cost of making them physically frail resulting in attacks that rely on brute force being more dangerous to them.

Imprint your imagination unto matter.

Effect

• Manifest or destroy an inorganic object/structure no larger than 5 m³

AND

• DURING UPTIME players will be presented by a GM with a choice of 3 different costs and will have to select one
• DURING DOWNTIME players will indicate the desired domain of the cost (physical, social, mental), from which a GM will allocate a cost

Usage

• This Spell can be used once per Uptime OR Downtime
  
• It may take some time for the Spell to take effect during Uptime ³⁾
  
• The effects of this Spell are, under normal circumstances, permanent… but are undone after a reset in the time loop

How is it learned?

• The next step after manipulating equivalence within oneself, is to manipulate it in the outside world. But in order to do so, a greater understanding of equivalence must be reached than before, which can be achieved through study or experience of sacrifice.

Examples

• A mage manifests a flood of water, washing away any enemies surrounding them. This comes at the cost of losing their voice (as they chose a social cost), unable to justify their actions to any who were unnecessarily damaged by the Spell.
  
• A mage destroys the weapons of an opponent, leaving the enemy defenceless. This comes at the cost of their unarmed combat ability (as they chose a physical cost), rendering them unable to resist if they let the enemy come too close.
  
• A mage raises a stone wall to defend themself and their allies from the breath attack of a monster. This comes at the cost of their Keepsake pendant (as they chose a physical cost), given to them by their deceased parent, which shatters as the spell is cast.

Twist reality into your desired shape and fill the tears.

Effect

• Manifest or destroy anything on a localised scale⁴⁾

AND

• Indicate what your desired cost is and it will be amplified to an appropriate magnitude by the GMs

Usage

• This Spell can be used once per Downtime only as it usually takes the form of a ritual and requires extensive planning and casting time
  
• The effects of this Spell are, under normal circumstances, permanent… but are usually⁵⁾ undone after a reset in the time loop

How is it learned?

• This Spell is a mark of pride kept by each and every distinguished mage - the standard for differentiating a novice from a veteran. To gain it one need only attain a deeper understanding of equivalence, which can be achieved through study or experience. However, it is worth noting that there are not that many people who have achieved this level of understanding, and so not that many people to learn from if you decide to study your way to greatness.

Examples

• A mage destroys the social affiliation of another individual with the Hunter faction, resulting in all Hunters forgetting that individual's ties to the Hunter faction. This comes at the cost of losing their own affiliation with the military faction (as they indicated loss of affiliation as a desired cost).
  
• A mage manifests a friendly monster to help them in future endeavours. This comes at the cost of losing their ability to adhere to complex plans, making it difficult for them to execute any manoeuvres beyond 'attack head on' (as they indicated loss of cognitive ability as a desired cost).
  
• A mage manifests an illusion of their own greatest fear in order to confront it and gain deeper understanding of their own past. This comes at the cost of them becoming more oblivious to immanent danger (as they indicated loss of perception as a desired cost).

No cost too great