Wizards of the School of Witchcraft are students of the occult nature of their abilities. Many other wizards see them as having drifted completely beyond the intended uses of their study to a more subverted or darker path of arcane knowledge.   Often these witches operate individually or in small covens, but almost always are cast out by society as a general rule.  If they are not, they choose to hide their knowledge or lore, keeping its power to themselves. The School of Witchcraft embody power at a price, and are thus also often confused with Warlocks.

Ritualist

When you choose this school at 2nd level, you gain the ability channel power to do things to tap into the divine world. You gain two ritualist uses.  As a bonus action, you may expend a use of ritualist to cast a spell on the Cleric spell list. When you use this feature, this spell must be the next spell you cast and you must begin casting this spell within 1 minute or it is lost. This spell consumes a spell slot as normal, and you must provide material components if the spell requires them. If you cast a spell of 5th level or higher using this feature you must expend two uses of ritualist.  You regain expended uses of this feature when you finish a short or long rest.  

Casting such spells takes a toll, and you must provide a visceral sacrifice to achieve it. When you cast a spell in this fashion you take 1d6 slashing damage for each level of spell. This damage may not be reduced in any way, such as by immunity or resistance.  

Occult Power

By 6th level, you learn to use the natural parts of your enemies to channel your magic. You can cast the following spells as a ritual, so long as they are in your spellbook:  bestow curse, dream, modify memory, and suggestion.  If you have a part of a creature (such as a vial of its blood, a scale, a lock of hair, or something similar), you may cast these spells as rituals and target the creature as though they were in range of the spell.  If you do so, the target has disadvantage on their saving throw.

When you cast a spell in this fashion it consumes the part of the creature you used for the casting.

Hex Magic

Starting at 10th level, you can hurl out hex magic towards foes with a flash of color in your eyes.  As a bonus action, choose one creature within 30 feet that you can see and that can see you and then choose one ability.  That creature must succeed on a saving throw against your wizard spell save DC or have disadvantage on all ability and saving throw checks with that ability for 1 minute.  

Creatures do not know you did anything of ill will unless you permit them to.  Otherwise, they must roll a Arcana (Intelligence) check against your Deception (Charisma) to determine if you had used some form of magical assault.

Once you use this feature, you cannot do so again until you finish a short or long rest.  

Mistress of Magic

Starting at 14th level, you can push your connection to the arcane to the utmost limit, tapping into its creative powers to fuel the magic that alters reality itself.  Choose two spells from any class list and add them to your wizard spellbook to be prepared normally.  When you cast these spells, treat them as a wizard spell.  They must be of a spell level of which you can cast spells.  When you cast one of these spells, the casting time changes to match that of a more ritual spell. If it is 1 action, it is now 1 minute.  If it is 1 minute, it is now 10 minutes.  If it is any longer than 1 minute normally, double the casting time when you cast it as a wizard spell.  

Additionally, whenever you gain access to learning new wizard spells of a new spell level (as as 8th-level spells at 15th level), choose one spell of that spell level from any class spell list.  To prepare and cast that spell, folllow the rules of this feature.