Necromancy

Necromancy was a school of Magic whose spells manipulate the power of death, unlife, and the life force. A wizard who specialized in the necromantic school was called a necromancer.
Necromancy is the study of magic involving life energy and manipulation of souls. Necromantic magic has many functions beyond simply raising the dead. Masters of this tainted field of magic can conjure festering diseases, harness the shadows into bolts of incendiary energy, and chill the living with the power of death. Spells involving the undead made up a large portion of this school, including animate dead and finger of death.
This school was the one most associated with lichdom, a process that allowed the caster to live (or rather, exist) in an undead state indefinitely by securing their essence in a receptacle known as a phylactery.
When a spell or effect rooted in a school of magic is unleashed, the weave takes on the characteristics and appearance of this magic, such as the characteristic green yellow glow of necromancy.

Culture

Necromancy is a magic focusin on the manipulation of souls, and souls tend to be sacred, or highly respected in most modern cultures. As such, necromancy is often perceived as evil, and banned.

Justice

The use of necromancy is highly supervised in Tana's Empire and the Lightfoot Kingdom. Anyone using necromancy to practice this kind of magic will be considered evil by the common folk.
Necromancy is illegal in the Ice-peak Concord. Anyone using necromancy will be going against the local law and will be arrested if by local authorities.
In Tana's empire and the Lightfoot Kingdom, it is the Academy of magic who regulate the use of necromancy through the law of arcane, and only the animation of the dead is forbidden.

"The animation of the dead, through the practice of Necromancy, is strictly forbidden. The study of Necromancy for the purpose of magical understanding shall be unrestricted."

— Law of Arcane

It is the College of Lore, the magical institution within the concord that forbid the use of necromancy, even research on the subject is banned.