Void Caster

Void casters are a standoffish and secretive lot, prone to delving into monster-prowled ruins and the dark corners of moldering libraries with equal caution; carelessly reading a text that might be sprinkled with alien glyphs and mysterious magics might be just as deadly as stumbling into a den of trolls, if not more so. As void casters continue to study such unknowable powers, they learn to properly wield it without destroying themselves or those around them.

Some void casters risk the darkness of the sake of gaining knowledge or strengthening one's defenses against that which lies beyond. Others succumb to the madness and corruption that void magic causes and become living conduits for the horrors seeking entry into the world.

Conjuration Savant

Beginning when you select this school at 2nd level, the gold and time you must spend to copy a conjuration spell into your spellbook is halved.

Whispers of the Void

Starting at 2nd level, as a bonus action immediately before casting a spell of 1st level or higher, you can utter a few words of an alien and mysterious tongue and weave its dark magic into the spell. The tainted spell disorients one creature you can see that the spell affects when it is cast. The creature has disadvantage on the next attack roll or ability check it makes before the start of your next turn. You must be able to speak to use this feature.

Rebuke from Beyond

Beginning at 6th level, when damaged by a creature within 60 feet, you can use a reaction to bark a destructive, alien word. If the creature can hear you, it takes necrotic damage equal to half your wizard level + your Intelligence modifier. You can use this ability a number of times equal to your Intelligence modifier (minimum of 1), and regains all expended uses after finishing a long rest. You must be able to speak to use this feature.

Void Echo

Starting at 10th level, when casting a spell that deals necrotic or psychic damage that targets a single creature, you can target another creature. Additionally, you have advantage on Constitution saving throws made to maintain concentration on conjuration spells.

Manifestation of the Nothing

At 14th level, you can choose a point you can see within 60 feet and use an action to utter a complicated phrase in the unknowable language of the void. The area within 20 feet of the point is shrouded in dim light for 1 minute. Any creature in the area that is hostile to the caster gains vulnerability to necrotic damage and has disadvantage on Wisdom checks. An affected creature that starts its turn in an area or enters it for the first time takes 3d6 necrotic damage, or half as much with a successful Constitution saving throw using your spell save DC. Once you use this ability, it can't be used again until after you finish a short or long rest. The caster can't use this feature if you can't speak.