There are 7 realms based on the 7 Deadly Sins, each one having 7 level of units that come in 3 different sizes, small (1 hexagon), medium (2 hexagons) and large (3 hexagons), usually the lower level ones being cuter and smaller, while gradually becoming larger and creepier to the higher end of the spectre. Each player is represented on the combat field by a special unit called the Dark Priest, that is able to make use of a scarce resource called plasma, using it to shield himself from harm and to materialize units in order to defeat all others who oppose him. Each materialized unit has a plasma cost, which is equal to this formula: unit level + unit size = plasma cost. There are no unit stacks and each unit is unique, only being materialized once by every player during a battle. The number under an unit depicts its remaining health if within a rectangle or the remaining shield if within an capsule, representing a number of hits the specific unit can take before actually being vulnerable. Killed units drop specific items that occupy their first hexagon, restoring health and or energy to other units that pick them; you can see the efficiency of a drop by hovering it and looking at the current unit's life and energy bar. Each unit has 4 abilities: a passive which can't be triggered manually, but might be in effect permanently or when certain conditions are met, a basic attack which is usually melee and affects a single adjacent hexagon, sometimes even having a special effect, a basic ability and an ultimate ability which is usually very powerful and can change the outcome of the battle. Active abilities usually require energy and sometimes even health. Each can be used once per round, with exceptions. Materialized units suffer from sickness, meaning they don't act the 1st turn and can't recover health or energy. There is no magic so there aren't any spell books, but thanks to their abilities, units can be used as spell pages, thought everything they're capable of doing can be explained by science, their bodies or the gear they may use.
Each unit has 9 statistics, being some of the main traits that define it's role on the combat field, for reference they're each explained when hovered the unit cards, but I'll explain them over here as well in way more detail.
Health - the amount of hitpoints an unit currently has, it's displayed under each unit in a rectangle; if an unit drops under 1, it dies, dropping an item if setting enabled. Corpses don't actually remain on the combat field.
Regrowth - after taking damage, units are able to heal themselves more or less each round provided they're not fatigued. Some units don't last very long in the line of fire, requiring constant breaks in order to refill.
Endurance - each round an unit can take a limited amount of damage and still be able to regenerate health and energy. The remaining amount is displayed in the interface, under the avatars of the queued units.
Energy - pretty much all abilities require some energy in order to be performed, the specific amount can be seen when hovering an ability or simply by selecting one provided it's usable from the current location and all its other requirements are met, the amount the ability will drain being indicated in the energy bar.
Meditation - an unit can recover some energy points as well each round, provided it's not fatigued. Even though most abilities can be used only once per turn, it's not very likely that all abilities can be used every turn, especially if the unit constantly gets fatigued. Make sure to shield your marksman units with tankier ones.
Initiative - this defines the position of the unit in the queue, higher level units being able to act faster during a round. Units that didn't act can choose to delay turn, being able to act at the end of the around along with the other units that delayed. The slowest unit can't delay if no other unit delayed before. When it comes to units with identical initiative stats, the older units gets to act first. Heroes tend to act based on player number at first, unless delaying, skipping or being influced by buffs or debuffs when their turn to act comes.
Offense - influences the output damage. If an ability performs area of effect damage and it hits multiple hexagons of a medium or large unit, then the damage will be higher, but not doubled or trippled.
Defense - is responsible for damage reduction. Larger units can take amplified damage from abilities that have an area of effect, by basically having a percentage of their defense being ignored, so be aware of this.
Movement - each unit can move a certain amount of hexagons every turn. It can do so in multiple actions performed and even before, in between and after using abilities. There are also abilities that can affect the mobility of the unit without requiring movement points, so make sure you use them to position strategically.
There are 9 common types of damages that can be either reduced or amplified, provided the specific unit has one or more abilities involving that mastery: pierce, slash, crush, shock, burn, frost, poison, sonic and mental.
The defense and offense stats are generic when it comes to reduction or amplifications, like the following formula shows: ability damage + attack damage * (offense stat of the attacker - defense stat of the attacked unit / number of hexagons hit + source stat of attacker - source stat of defender) / 100. Minimum damage is 1.
There is also a rare type of Pure damage that can't be reduced. Both stats and masteries can be affected by abilities, hovering on each one in the unit cards ingame will display a list of the buffs and debuffs affecting it.