System Mechanics
SP
SP, or Sanity Points, directly affects the state of your characters and how they perform in combat. SP, depending on whether it is positive or negative, increase or decrease your chances to flip a heads respectively. A Sinner's SP will increase as they acquire positive outcomes(Winning a clash, killing an enemy, etc), and decrease as the opposite happens. SP can also be affected by other factors directly, such as the 
Sinking When hit by an attack, take fixed SP damage by the effect's Potency.
(Abnormalities take Gloom damage instead.)
Then, reduce its count by 1. status and passives such as R. Corp Ishmael's Brainwave Focus. This is visually represented with blue and red arrows appearing near the Sinner's SP bubble, on the right side of their HP bar. Generally, SP is only affected minimally by factors outside of what outcomes the Sinner acquires themselves - even if you are doing well overall, if one select Sinner is losing most of their clashes, their SP will drop into the negatives very easily. See more about E.G.O. Corrosion below.
Each point of SP adds 1% modifier to your likeliness to flip heads. As such, having +20 SP would increase your chance of flipping heads to 70%, while having -15 SP would result in a 35% chance. Note that this is your likeliness to flip heads, regardless if the coin is positive or negative. How SP increases and decreases can be viewed in-game.
Additionally, being at low SP applies additional status effects on Sinners and human enemies (
Overwhelmed Status applied to low morale humans (below a certain SP threshold). Inflicts 2 
Attack Power Down Attack skills lose final Power by the effect's Count for one turn. at start of turn. and 
Panic Status applied to humans in panic. Inflicts a variety of random effects, such as Attack Power Down Attack skills lose final Power by the effect's Count for one turn. and 
Immobilize Cannot act this turn. . ) that apply negative effects, such as Attack Power Down Attack skills lose final Power by the effect's Count for one turn. .
Effects that are applied to specific entities at low SP, including Sinners, can now be viewed in-game, with a few major types of "Panic" effects.
E.G.O. Corrosion
A Sinner's SP also ties directly into their E.G.O., and once it falls low enough you gain access to the Corrosions of those E.G.Os.
You might note that a vast majority of Corrosion E.G.O. Skills have a Minus modifier on heads, meaning that upon activation at low SP, the Skill is more likely to end up with a higher roll.
There are two ways to enter E.G.O. Corrosion. Manually activating an E.G.O. while at negative SP(~-30 and below), using a non-personal E.G.O will cause the Sinner to enter Corrosion at a chance that increases as your SP lowers, using the Corroded version of their E.G.O. Skill and turning into the E.G.O's Corrosion form. Alternatively, once they fall to -45 SP, the lowest it can be, they will immediately Corrode on their next turn, assuming they are not staggered. This does not require E.G.O resources(bar on the right side of screen) to activate, but will subtract those resources the E.G.O requires, and can put you into the negatives.
While in the Corroded form, denoted by 
E.G.O Corrosion Status applied to Sinners who have activated a non-personal EGO below the prerequisite SP threshold, or fallen to -45 SP in order to activate Corrosion.
The amount of turns which the Sinner will stay in the Corrosion form for is denoted by the Count of this status effect. , the Sinner has all of their Skills replaced with their Corrosion E.G.O. Skill, and do not have access to their normal Skills. Sinners cannot be Corroded from their personal(starter) E.G.Os, meaning that to access Corrosion you will need to acquire E.G.Os from the gacha or battle pass.
The majority of these Corroded Skills are [Indiscriminate], meaning that you will not be able to manually direct them, and they will instead target random Skill slots on both allies and enemies. HOWEVER, which target(s) they choose is predetermined before combat starts and differs for each instance of the Skill currently available to the Sinner. Before combat starts, you can view what targets your Corroded Sinner can choose, and plan out your turn around them. Often, you will be able to avoid friendly fire completely with single-target Corrosion Skills.
Offense and Defense Level
These two stats are tied to the level and growths of your Sinners' Identities, and are important determining factors in how well they perform in two major aspects, clashing and survivability. Identities with a higher Offense Level will be better at clashing, and those with a higher Defense Level will be able to survive more hits.
For every increment of 3 that a character has over their opponent in Offense Level during a clash, they gain 1 additional power to all rolls during the clash only. This does not affect damage dealt.
When a character is on the receiving end of an attack, their Defense Level is taken into account in damage calculation, and applies a percentage modifier to how much damage the attack deals. The formula used is as follows:
[Modifier] = ([Defense Level] - [Offense Level]) / (Abs([Defense Level] - [Offense Level]) + 25)
Put simply, the damage dealt by an attack is increased by 3% when the differential between the attacker's Offense Level and the defender's Defense Level is 1, and 28% when the differential is 10. As the differential increases, returns diminish, and when the Defense Level is higher than the Offense Level, the modifier is applied as a negative instead, reducing damage dealt.
