Inner Light and Shadow
Overview
All beings naturally contain some amount of inner Light and inner Shadow. Together, inner Light and Shadow are measurements of a being’s balance of good and evil, operating on a spectrum - if either is reduced, a being’s personality and grip on morality may be forever altered.
An average individual will have approximately equal levels of inner Light and Shadow. However, through various arcane methods, an individual may disrupt this balance in favor of one or the other, allowing them to tap into their emotions to use certain elemental powers or abilities; the more unbalanced their inner Light or Shadow is, the more pronounced these abilities will be. If an individual is already associated with an element and their inner Light or Shadow is unbalanced, they will be able to use both their original element and the new element in conjunction, albeit not to the full potential of either. A rare few beings have purged either their inner Light or inner Shadow entirely (for example, the Makuta), becoming wholly aligned with the remaining element.
The most common way to change one's balance of inner Light and Shadow is through intensive training and prolonged meditation on certain emotions and values; for Light, these are peace, mercy, and understanding, and for Shadow, these are anger, fear, and vindication. Causing even a small change in the balance of inner Light and Shadow cannot happen purely by chance.
There are also several means of draining an individual's inner Light by force, including the power of the Kanohi Avsa, as well as the Shadow Leeches developed by the Brotherhood of Makuta. If a being is partially drained of their inner Light, they will usually be able to naturally regenerate their lost Light over time; however, full drains (or partial drains inflicted by Shadow Leeches) instill a mental block in their victims that prevent this regeneration process. This mental block can be broken by sonic waves of a specific duration and frequency (such as the screams of the Klakk).
In the Doronai Nui
All beings have within them some measurement of Light and Shadow, measured on a two-scale system. By default, an untainted being has within them a value of 2 Inner Light and 2 Inner Shadow. These values may be reduced in order to achieve a desired effect: the ability to use Elemental Light or Shadow.
Inner Light and Shadow can be reduced through a variety of methods. External sources include but are not limited to specific pieces of technology (such as the Kanohi Avsa), certain Rahi, or purpose-created entities (such as Shadow Leeches). A being can also reduce either value by training. The specifics of such training should be left up to the discretion of the GM. If a being’s Inner Light or Shadow is reduced, unless otherwise specified, will return to its original value at a rate of 1 per 6 months.
If a being’s Inner Light or Shadow is reduced to 1, they gain the Eyakaki Template (with the element gained based on whether Inner Light or Shadow is drained), assuming they have an original element. If they lack an original element, no change is noticeable. If a being has both their Inner Light and Shadow each reduced to 1, no change is noticeable - save emotion, which may be dulled. Additionally, if a Toa with access to the Nova Blast ability uses this while under the effects of the Eyakaki Template incurred from having their Inner Light/Shadow drained, the damage their Nova Blast deals is half of their Primary Element’s damage and half of their Secondary Element’s damage.
If a being’s Inner Light is reduced to 0, their Element (if they have one) is replaced by Shadow, replacing their Attribute Scores and Talents with those associated with Elemental Shadow, as well as gaining any Proficiencies from Elemental Shadow, and keeping any Proficiencies from the wielder’s previous element. Likewise, if a being’s Inner Shadow is reduced to 0, their Element is replaced by Light, replacing their Attribute Scores and Talents with those associated with Elemental Light, as well as gaining any Proficiencies from Elemental Light, and keeping any Proficiencies from the wielder’s previous element.
Additionally, beings may have their colors changed if they lose Inner Light or Shadow. A being whose original element is Light that has their Inner Light reduced will have their natural colors replaced with darker shades of their original color, or black (though Av-aligned beings who still have access to their original element may change this color by using their Tribally-Linked Ability). Likewise, a being whose original element is Shadow and has their Inner Shadow reduced will have their natural colors replaced with gold and white.
If a being has their Inner Light reduced to 0 and their Inner Shadow reduced to 1, they instead are treated as having the Eyakaki Template as though their Inner Light had been reduced to 1 (and vice versa).
If a being’s Inner Light and Shadow are both reduced to 0, an affected being will lose grip on morality, effectively losing any form of empathy or understanding. Most Rahi by default have an Inner Light and Shadow of 0.
Under most circumstances, beings elementally associated with Light or Shadow are created or corrupted from another element, with Elemental Light or Shadow being rare and outright unheard of naturally. If a being aligned with another element is transformed into a being elementally aligned with Light or Shadow (with the other element typically being lost), or are otherwise transformed into a being of Light or Shadow, any Skill or Crafting Proficiencies gained from becoming elementally aligned with Light or Shadow are treated as Expertise 1 if the being already had a Proficiency with them.
If an affected being has either their Light or Shadow drained and lacks a normal element, any Attribute Score bonuses are replaced by Elemental Shadow, and the wielder gains the following ability:
Elemental Powers
Beings who have been tainted by a given source have the ability to exert control over a specific element, dictated by the drainage of their Inner Light or Shadow. This pool regenerates over time. When your Inner Light or Shadow is drained, your minimum EE value is equal to 10. For every level after this, add 1d4 + your Elemental Attribute Score modifier (only if positive), and then divide the result by 2. Add this result to your previous EE total. Such beings can have no more than 40EE.
Beings that have had their Inner Light or Shadow drained that do not normally have the ability to use elemental abilities only have access to the following Forms: Bolt, Feint, and Elemental Strike. Drained beings are able to use the Telekinetic Manipulation of Elements and Elemental Absorption abilities as well. In any of these forms, you may only invest 2SPI into any individual Subcategory. For example, the strongest Elemental Strike a drained being can perform is 3d8 with 2 Riders.
When using your Elemental Powers, your Attack Rolls are 1d20 + your Elemental Attribute Score Modifier + your Proficiency bonus. If you were required to make an attack roll to hit with the effect (for example, with Bolt or Elemental Strike), you may add your Elemental Attribute Score Modifier to the damage roll. If your Elemental Attack requires a DC, it is equal to 8 + your Elemental Attribute Score modifier + your Proficiency bonus. You only add your Elemental Attribute Score modifier if it has a positive value.
Beings that are innately associated with Elemental Light or Shadow are affected by drainage differently. If a being elementally associated with Light has their Inner Light reduced to 1, every time they spent EE that exceeds their Turn Threshold, or reaches Half their EE Pool’s Threshold (see Elemental Fatigue), they must make a WILL Save (DC 1, +1 for every three times this occurs, having this DC increase reset upon having their Inner Light restored); on a failure, their Inner Light is reduced to 0. The same is true for beings elementally aligned with Shadow (reversed). Additionally, they cannot regenerate EE lost from their original element until their Inner Light or Shadow is restored.
When Matoran have their Inner Light drained, they lose their normal Tribally-Linked Ability but do not gain the ability to shroud themselves in darkness (see the Tribally-Linked Abilities of Shadow). Likewise, if a Matoran's Inner Shadow is drained, they do not gain an Av-Matoran’s Tribally-Linked Ability to change the color of their armor. In either case, they could however learn to use these abilities if they were to become a Toa.
Other
Beings from outside the Matoran Universe have a measurement of Inner Light and Shadow. While their personality, emotions, and feelings may change if either is drained, they will never have access to the elemental abilities of Light and Shadow, if derived from draining Inner Light or Shadow.