The Wizard

Clad in the silver robes that denote her station, an elf closes her eyes to shut out the distractions of the battlefield and begins her quiet chant. Fingers weaving in front of her, she completes her spell and launches a tiny bead of fire toward the enemy ranks, where it erupts into a conflagration that engulfs the soldiers.
Checking and rechecking his work, a human scribes an intricate magic circle in chalk on the bare stone floor, then sprinkles powdered iron along every line and graceful curve. When the circle is complete, he drones a long incantation. A hole opens in space inside the circle, bringing a whiff of brimstone from the otherworldly plane beyond.
Crouching on the floor in a dungeon intersection, a gnome tosses a handful of small bones inscribed with mystic symbols, muttering a few words of power over them. Closing his eyes to see the visions more clearly, he nods slowly, then opens his eyes and points down the passage to his left.
Wizards are supreme magic-users, defined and united as a class by the spells they cast. Drawing on the subtle weave of magic that permeates the cosmos, wizards cast spells of explosive fire, arcing lightning, subtle deception, and brute-force mind control. Their magic conjures monsters from other planes of existence, glimpses the future, or turns slain foes into zombies. Their mightiest spells change one substance into another, call meteors down from the sky, or open portals to other worlds.

In The Nameless Trilogy World

The wizard represents the most infamous, albeit not the most prolific, of the classes. The nations of the world have long sought to study the ways of magic-wielding for the purposes of control, command, and warfare. Individuals gifted in magic and willing to spend years studying the art will find numerous universities to study. Or a young wizard may apprentice themself to a traveling archmage who wishes to pass on his wisdom to the next generation. There are universities of magic in almost every city, lonely wizard towers in far-flung villages, and even the occasional military college where skills can be honed and tested.
But magic is not without a painful legacy, as anyone with a knowledge of history can tell you. There are those scared of what may happen if another war on the scale of the Great Human-Elf War were to break out. A single wizard with enough power and knowledge could level an army or sink an entire ship and crush an entire village. There are those few individuals who believe in keeping track of wizards and hunting down the most dangerous ones. And less we forget the legacy of Necromancy, which is still heavily outlawed in every nation to today, people today will still recount the horrors of what human necromancers did to the elves.
Choosing a wizard is choosing to enter into this long legacy, whether you were involved in it or not. Anyone who chooses to study magic could potentially gain more power than kings or entire armies, to wreak havoc and bring great destruction. How you choose to use that power will define you as a wizard in the eyes of others and in the eyes of the party. How did you come to the decision to study magic, and how do you want to use it? What is your end goal? Do you have a line that you will not cross or how close are you willing to toe that line between what is good and what is morally gray?

Resources:

• Player's Handbook
• Xanathar's Guide to Everything
• Xanathar's Lost Notes to Everything Else
• Sword Coast Adventurer's Guide

Subclasses:

• School of Abjuration (PHB)
• School of Conjuration (PHB)
• School of Divination (PHB)
• School of Enchantment (PHB)
• School of Evocation (PHB)
• School of Illusion (PHB)
• School of Necromancy (PHB)
• School of Transmutation (PHB)
• School of War Magic (XGtE)
• School of Beguilement (XLNtEE)
• School of Reconstruction (XLNtEE)
• School of Bladesinging (SCAG)