EMCore - The Empyrean Core Game System

The following rules make up the Empyrean Core Game System (aka EMCore). 

Overall, the game system of Empyrean is modular, and can be extended in many ways. Even some Core Mechanics highlighted here can be altered within a certain context.

1. The Dice: 
1. Empyrean can be played with any dice. Currently, the core system is being balanced around using primarily the d12 dice. In its extended version, the game system has also been tested and balanced around using primarily the d20 dice.
2. Each dice has the following potential results: Botch, Failure, Success, Critical Success. 
3. The Botch Number is 1. Botch counts as -1 success for the entire roll. 
4. Failure counts as 0 success. Success counts as 1 Success, and 
5. Critical counts as 2 successes.
6. The Success / Target number determines the minimum result needed to score a success. So for a roll with 8+, any result of 8 or higher is a success (and any result between 2 and 7 is a failure).
7. The Critical number determines the minimum result needed to score a critical. So for a roll with 10+, any result of 10 or higher is a critical is a critical, whilst any result between the critical number and the success number is a success, and any result other than those is a failure or a botch if that result is 1.
8. Each roll is usually made by at least 2 dice while unmodified.
9. The basic number of dice rolled is determined by the Aspect involved in the roll.
10. The basic formula to calculate the number of dice is 1 + (Aspect Level / 2 - round up).
11. Modifiers add or remove dice from rolls. 
12. In Empyrean the majority of rolls are opposed by other rolls. This is called a contest.
13. The winner of the contest is the one to score the most successes.
14. Any roll that is not a contest is called a test.
15. Tests determine what constitutes a success on an individual basis. Some harder tests require critical successes only.
16. Every contest is won by a success margin.
17. The success margin is equal to Victor Successes - Enemy Successes.
18. The success margin determines the actual amount of success... For example in combat it could determine the damage dealt.
19. Generally speaking: More successes scored = better result.
2.  The Aspects. Aspects are not attributes. They are more like "classes". They don't develop further. In the core system, however, the Aspects double as Attributes as well. They still don't have some development mechanism. The style of play of Empyrean and other games similar to it makes use of the following Aspects:
1. Force: The character's strength, courage, melee combat prowess, physical might, aggression, and ability to asset, and intimidate. Among other things Force is used to roll for melee combat, affects the player's ability to fight with heavy weapons, and the damage dealt in melee combat.
2. Adeptness: The character's skill, agility, cunning, diplomacy, charm and wit. Adeptness is used to roll for ranged combat, dodge, evasion, guile, trickery, seduction, charm, stealth and a slew of other actions. 
3. Fortitude: The character's stamina, resolve, endurance, tenacity, discipline, stoicism and self-control. Fortitude is used to roll to soak damage and resist various adverse effects. It also affects the player's ability to wear heavy armor. 
4. Insight: The character's intelligence, perception, wisdom and other mental and emotional faculties, including empathy. It also affects the order of play during turn-based actions. Insight has no martial aspect, but drastically affects the player's knowledge, awareness and understanding of in-game information, and thus it often enables players with higher insight to participate more intimately into the ongoing story. It is also favored by occultists because it enables them to know and perform more arcane spells, but in the world of empyrean such knowledge may have side-effects when the power it taps to is non-trivial.
5. Spirit: The character's virtue, inspiration, faith, ideals, moral and spiritual faculties. Also their link to the supernatural, the base of their willpower, and their ability to tap into the true, natural, mystical magic of the world. 
6.  After determining what kind of character they are going to play, the players move on to prioritizing the 5 Aspects. The players have 5 levels to choose for their aspects. The Highest Aspect Level is 5. The Lowest Aspect Level is 1. According to the Aspect Level chosen, the players receive the following:
1. Roll 2 dice. Success 8+. Critical 12.
2. Roll 2 dice. Success 7+. Critical 12.
3. Roll 3 dice. Success 7+. Critical 12.
4. Roll 3 dice. Success 6+. Critical 11+.
5. Roll 4 dice. Success 6+. Critical 10+.
3. All players begin with Might 1. Players with Force Level 5 receive +2 Might, while those with Force Level 4 receive +1 Might.
4. All players begin with 3 Health Levels: Bruised, Wounded, Crippled. Players with Fortitude Level 5 gain 2 extra Bruised Health Levels. Players with Fortitude Level 4 gain 1 extra Bruised Health Level.
5. All players begin with 3 Movement. Adeptness Level 5 grants +2 Movement. Adeptness Level 4 grants +1 Movement.
6. All players begin with 3 Willpower. Players with Spirit Level 5 gain 2 bonus Willpower. Those with Spirit Level 4 gain 1 bonus Willpower. Willpower can be spent temporarily by players to:
• Gain Inspiration (+1 dice bonus per developed Character Drive).
• Overcome some psychological impediment.
• Move up to your movement.
• React with a roll to some ongoing situation.
7. Combat. The basic combat system is a series of dice contests. For melee combat both sides either roll Force (melee combat), or one side rolls Force and the other Adeptness (dodge). For ranged combat both sides roll Adeptness (the attacker rolls ranged combat, the defender rolls dodge). Initiative is determined by Insight Aspect Level. The winner of the contest deals damage to the loser if they were attacking. The damage is equal to a base amount plus the net successes of the winner's victory. The loser soaks the damage by rolling fortitude. If they fail the soak roll they suffer one wound.
8. Development. The basic development system is very simple. The player marks a single trait in their character sheet that they wish to improve and notifies the storyteller. The storyteller plans out a progress chart of improvement for the player's choice, choosing anything between 10 and 100 progress steps. He does this for all players, and must come up with a consistent system. At the end of each session the storyteller moves the player's progress at least one step closer to the target. He can choose to grant more steps to a player who had significant achievements, or to the entire group if all of them made great breakthroughs during the game session.
9. NPCs / Creatures. Generate in the same way as player characters, then adjust as follows:
• Minor NPCs / Creatures: such as minions, trivial characters etc. roll a maximum of 2 dice on any roll. Health: 1. Unable to use Willpower. 
• Regular NPCs / Creatures: friendly NPCs, companions, followers, other allies. Roll a maximum of 3 dice on any roll. Health: 3. Willpower: 3. Can use Willpower in life-threatening situations.
• Major NPCs / Creatures: such as boss or lieutenant characters, big monsters, major antagonist, or other significant story characters. (They are few in number. Usually 1 or 2 of these appear in a game session). Calculate all stats, including health and willpower as normal. Increase Health, Willpower, Movement, Might and Dice rolled by at least +1. Powerful enemies and creatures may have very big health (10+). They can use willpower casually, or as they see fit.

Character Sheet that can be used to run a game using EMCore: Character Sheet