Necromancer

The Necromancer is a master of bone and death. Wherever corpses are is where a Necromancer thrives, and his bond with the dead is hard to break, if not impossible, without killing him. A Necromancer's primary feature is that they can raise the dead again. Not as a mindless thrall, or even as a fully functioning creature, but as a completely obedient skeleton. 

Even a Necromancer's other spells are affected by their study of undeath; even those which should be pure arcane force instead represent the amount of time and effort involved in mastering death itself. 

Necromancers are often pale as snow, not from any disease or affliction, or even a rebound effect caused by the powers they harness, but simply because they spend so much time in crypts that they rarely if ever see the sun. 

Necromancy Savant

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

Disciple of Undeath

Your study of necromancy begins to affect your standard spells. At 2nd level, you learn the Cantrip Manipulate Corpse. This does not go against the number of cantrips you can know. Furthermore, your wizard spells begin to change to fit your specialty. The spell Shield conjures a wall of bone to protect you from an attack, Mage Armor conjures a maelstrom of bone to increase your defence, and Magic Missile sends spears of bone at your foes. They also become Necromancy spells for you but otherwise function the same mechanically. 

Skeletal Army

At 6th level, you can spend 10 minutes to create a skeletal warrior from a humanoid corpse. The skeleton uses the standard skeleton stat block, but it does not have weapons when it is born. They cannot communicate other than through simple gestures. You can have a number of skeletons equal to half your Wizard level, rounded down. If you summon a new skeleton while at your limit, the oldest skeleton crumbles to dust. 

In combat they roll their own initiative, but as a group, so they move on the same count as each other. When they are reduced to 0 hit points, they crumble into dust. They can take actions as normal. 

Skeletal Mage

At 10th level, you can imbue a skeleton minion with a small amount of arcane power. When you have the maximum number of skeletal warriors, you can use an action to turn one of them into a Skeletal Mage, with the stat block of a regular skeleton but with a few benefits. A skeletal mage has an Intelligence of 16, and knows two cantrips and two first level spells of your choice. They have 2 first level spell slots and share your Arcane Recovery feature. They use Intelligence as their spellcasting modifier and the spells they know must be ones you know or have in your spellbook. 

You can have one skeletal mage at a time, and it does count against your number of skeletal minions you can have summoned. 

Skeletal Mastery

Your mastery over the balance between the forces of life and death has made your skeletons deadly efficient. Your skeletons lose their vulnerability to bludgeoning damage and gain the feature Undead Horde, described at the end of the description. Additionally, your Summon Skeleton feature becomes an action, and you can cast it through your skeletons using their reaction. You can have 2 Skeletal Mages at a time. 

Undead Horde. When a skeleton makes an attack roll against a creature, and there is another skeleton within 5 feet of them, they gain advantage on the attack as long as neither of them have taken damage since the start of the round.