This page of the Divinity Original Sin 2 guide contains a detailed descrption of Witch. You'll get acquainted with the basic information on this class, recommended playstyle, as well as its biggest advantages and potential disadvantages.
Witch is one of the hybrid classes that combines features of an assassin (Scoundrel abilities) and a mage (Necromancer tree). Thanks to that, Witch can hurt enemies thanks to spells and, when a situation calls for it, they can get behind enemy's back and use a dagger to deal additional damage. This class can deal a lot of physical damage, curse enemies and summon monsters that will fight alongside your team.
Below, you can view starting parameters for this class.
In the case of Witch, there are two attributes that are buffed by default.
A bonus to Finesse can be useful when you are using ranged weapons as well as daggers but it can also strengthen abilities from Scoundrel and Huntsman trees.
This bonus allows for a greater effectiveness of attacks and dealing more damage when using elements but also spells. Additional Intelligence also slightly increases magic armor.
A point of Constitution increases amount of health points which gives a character more vigor.
Abilities and Talent
In the case of Witch, there are four abilities.
A bonus to damage dealt by abilities from this school goes perfectly with additional Finesse point - most of Scoundrel's abilities require a use of daggers.
Additional percentage in stealing health, based on amount of dealt damage which has a direct influence on enemy's health, allows for a gradual regeneration. Thanks to that you can focus on dealing damage.
A bonus to Persuasion allows you to have a greater influence on NPCs.
Leech - allows you to regenerate your HP while you are standing in a puddle of blood.
Raise Bloated Corpse
A very useful ability that allows you to summon a monster out of a corpse of another enemy. The monster has a lot of health points and it can explode, dealing area damage.
Destroys X points of magic armor (depends on character's Finesse attribute) and puts a target to sleep if it deosn't have magic armor.
Remember, that this ability doesn't deal any damage.
This ability allows you to deal physical damage (which are blocked by physical armor, not magic, unlike most of the spells) and heal your character by an amount of dealt damage.
Witch and Races
Of course, the lack of default predispositions that provide bonuses to attribute does not mean that you cannot create a character with this class and of this race, but you should keep in mind that the effectiveness of such a character, in the battlefield, may be lower than in the case of other races.
In this case, parameters do not harmonize in 100%, but thanks to the base bonus to Wits, your initiative factor is much higher and it allows you to find a more convenient position in battle, or eliminate threats before they can do any damage.
Just like in the case of Elf, there are no racial attributes, nor abilities, which would support creating Witch of this race.
The additional two points to Intelligence and a passive bonus to Persuasion especially predestine Lizards to be Witches.
Which abilities are worth choosing?
A Witch has access to two schools (Necromancer and Scoundrel) which means that they can choose from 8 starting abilities. However, the default starting abilities are very useful and selected wisely - you shouldn't change them because this will only lower this character's effectiveness. Because of that you should use Raise Bloated Corpse, Chloroform and Mosquito Swarm.