In Divinity: Original Sin 2, classes can be broken down into the same three groups as the original game: warrior, mage and survivor. Furthermore, there are several hybrid classes that cross over between two of these groups.
Fighters are the front line combatants in any battle. Focusing on Single Handed combat and shield defence, fighters initially begin with Bouncing Shield and Fortify, allowing them to fight from range while gaining ground on their target and replenish their Physical Armour when the need arises.
With the inclusion of Battle Stomp in their initial skill itinerary, fighters are also flexible enough to move to dual wield or two-handed weapons, without fully sacrificing their ranged capabilities.
Knights are the Two-Handed counterpart to the fighter. Although attacks may require more Ability Points (AP) per attack, their weapon damage compensates for this, often with additional range on their close quarters combat. In addition to this, knights begin with the Opportunist talent, allowing them to make a strike of opportunity when a target moves past them.
Furthermore, knights can sacrifice evasion and resistance to gain additional speed in battle due to their Rage skill and can also close in quickly (and strike multiple targets at once) with Battering Ram.
The main focus of a conjurer on the field of battle is to provide combatant support; by summoning additional units and defences onto the field. Although not quick to fray due to the bulk of their initial abilities revolving around summoning incarnates and defensive totems, they can potentially double offensive capabilities in a single turn.
Enchanters are support combatants, focused initially in the Aerotheurge and Hydrosophist arenas of magic. Initially beginning with Restoration, they can assist their party with healing skills (or take on the undead if required) and are capable of defending themselves with Hail Strike and Electric Discharge. As a wand wielding class, they can further expand their elemental capabilities by diversifying their equipment, avoiding the need to invest in other elemental trees; albeit these elements will not prove to be as powerful or able to target as far as those with investment in part due to their initial talent Far Out Man, which extends the range of skills.
As with the conjurer, enchanters are also capable of identifying equipment.
Witches are magic users who wield both life and death in the forms of geomancy and necromancy. Where the enchanter focuses on damaging from afar, the witch focuses on weakening and manipulating the enemy. Starting out with Poison Dart and contamination from the geomancer skill set and Blood Rain from the necromancer tree, once an enemies Magic Armour has been taken down battle can be drawn quickly to and end through damage over time attacks.
Wizards are the fire and brimstone of the mage classes, focused initially in the offence Pyrokinetic and Geomancy fields. These two skill trees go hand in hand in combat, with Fossil Strike leaving a pool of oil underneath the target, waiting to be ignited by a searing dagger or another form of ignition.
As with the enchanter, wizards start out with the Far Out Man talent, enabling them to fight from further afield.
Rangers are fast moving ranged combatants, their arsenal comprising of bows with support skills like First Aid and Haste enabling them to recover their energy (health and ability) quickly. Furthermore, rangers are luckier than most, finding rare items more frequently than most.
Rogues are combatants who tend to operate from the shadows at close range. Dual wielders of daggers, they prefer to attack from behind and backstab their opponents in close combat, or throw searing daggers from afar.
In a pinch to seal the battle before their next turn, they can push themselves with a jolt of natural adrenaline to try and get in another strike, at a reduced cost to their Ability Points for the next turn only.
Battlemages are close quarters combatants with status affecting magic (starting with Blinding Radiance and Shocking Touch) that enables them to hinder the enemy. They are also quick into battle with their battering ram skill as with the knight, allowing them to knockdown several targets at once.
As with the battlemage, clerics are also close combat mages; however, their magic is more imbued in healing and draining their targets in the name of self preservation.
Inquistors, like clerics and battlemages are close combat magic users. Initially more focused on close quarters combat with Battering ram and critical blow skills, they dabble in the necromancy arena, targeting their foes with physical damage and statuses.
Defeating their opponent gives them a boost in combat, boosting their Ability Points by 2; allowing them to return (or remain) in the fray for a while longer.
Unlike the other hybrid classes, metamorphs take from all three of class structures. Their initial power stems from polymorph magic, which enables them to change their form (or that of others in some cases), providing them additional means of fighting; with skills such as bull horns allowing them to charge at enemies. This ability also provides additional means of movement, both within and outside of battle; one can spread their wings and move from a high-low vantage point (or vice versa) without a ladder or traverse canyons, gaining access to otherwise inaccessible locations or reducing travel to said point.
From a close quarter combat perspective, the metamorph shares abilities with the knight, with 2 handed combat skills and the opportunist talent, sans the strength focus; two handed swords are largely out of the question for this class, but staffs and spears are the viable alternative with their focus on finesse; an attribute more closely aligned with the survivor class.
Shadowblades are closer to rogues than being a hybrid class, the key difference being they also have a reliance on polymorph skills, using Chicken Claw to disable their opponents attacks and Chameleon Cloak to hide in the shadows, allowing them to invisibly move from position to position on the battlefield.
Their stealth abilities are enhanced by their initial talent, guerrilla, adding an additional 10% of damage to every blow struck from a sneak position.
Wayfarers are a mix between then ranger and a mage. Armed with bows and the rangers combative abilities, they are armed with geomancy skills; in combination this gives them the ability not to only do earth damage and leave pools of oil on the battle field, with a well places fire arrow they can also cause widespread fire damage, without support.