Void Magic is a rare Talent involving the manipulation of emptiness and nothingness.
The aura color associated with Void Magic is deep purple.
Antimagic is the antithesis of mana, and is capable of neutralizing spells and enchantments it's directed at. A strong enough antimagic field can prevent spells of any type from being cast in it. Unlike wards, antimagic relies on being able to absorb mana rather than deflect it.
Beyond the Veil, deeper than the Ethereal Plane, lies the Void. The Void is extremely dangerous and only someone capable of using Void Magic can survive in there for long. Other magic doesn't work properly there, horrors that cannot exist within the universe reside there, and space does not have any normal meaning. Even if a Void Mage survives the trip, they're likely to become trapped out there if they're not careful.
To a skilled Void Mage, however, the Void is both prime real estate and their greatest asset. Like Dream Magic, the Void can be used to allow teleportation to places that it would not normally be possible, without restriction or limitation. While wards that can stop dreamwalking are possible, there are none that can stop Void, due to its very nature.
A Void Mage may jump into the Void to hide, or even construct themselves a base or home within the Void. A sufficiently powerful Void Mage can manipulate the fabric of reality outside the universe. That's also the reason why it's rare to see powerful Void Mages. By the time they get to that point, they've likely left the universe and have built their own small world out of raw chaos somewhere.