After Vecna destroyed much of the magical knowledge on the world and the most powerful mages were killed a group of low and mid-level mages got together to try and collect and preserve as much magical knowledge as possible.

The most elite group of assassins. Use both magical and mundane arts to kill their targets.

A cabal of powerful individuals with hidden intentions 

The premier Adventuring Guild

A strong criminal organization in the sundered kingdom. 

The Nightingales are a secret group of rogues, spies, and bards who travel collecting secrets with the intention of trying to thwart evil.

They formed alliances with dragons and enslaved giants by using secrets of magic stolen from the gods in their efforts to increase their own power. With their enslaved giant armies, the armies of Vecna built massive tombs, enormous magical constructs, and staggering monuments, some that survive today, mute testimonies of a mysterious age long past.

Followers of Asha

The Black Robes are Necromancers loyal to Vecna. Part of The Noxumbra 

Started after Vecna’s attack on Bard Gate. The Crimson Dawn is an order of mostly humans who view magic in all forms as a destructive force and believe that practitioners of magic are thus evil and need to be eradicated. They have grown large and powerful. They specialize in hunting and killing magic users of any kind with a special focus on arcanist

An ancient order of historians, philosophers, magic wielders, teachers, and researchers. They are martial mages charged with protecting both their people and knowledge. Very few even know of them. Those that due are mainly scholars and they believe that the group died off centuries ago.

Known by various names in different parts of the world:

The Mages of Saruun

Loreguard Warden

Loreguard Sentinel

Sanctum / Enclave  of the Loreguard Brotherhood