Shadowmancer

A long time ago you were a mage training in the Wizards School of Abjuration. After a terrible accident from a spell gone wrong you were thrust through a portal and deposited into the Shadowfell where you were trapped and your magic changed forever. As the years went by you started to develop arcane gifts from your changed shadowy power. One day finding a portal back home, completely by accident, you rushed through expecting to be welcomed. Alas your dark power was a source of fear to them and you were scorned and chased away. Striking out on your own, you started to develop your gifts further.

Shadow Savant

Beginning when you select this school at 2nd level, the gold and time you must spend to copy a spell into your spellbook is halved. All spells written into your spellbook have their damage changed to cold damage due to the influence of the Shadowfell.

Shadow Armor

Starting at level 2, you gain the ability to cast Mage Armor at will but your Mage Armor is a bit different. Instead of deflecting attacks, it allows them to harmlessly pass through your body.

You can also weave shadow around yourself for protection. When you cast an abjuration spell of 1st level or higher, you can simultaneously use a strand of the spell’s magic to create a magical ward on yourself that lasts until you finish a long rest. The ward has a hit point maximum equal to twice your wizard level + your Intelligence modifier + your Dexterity modifier. Whenever you take damage, the ward takes the damage instead. If this damage reduces the ward to 0 hit points, you take any remaining damage.

Shadow Step

Starting at 6th level, While a shadow is available you step into it and teleport to another shadow within 60ft of you. If you choose to you may remain inside the shadow for up to 1d4 turns, but if you do so roll a D20 Con save DC(12) or take 1d6 cold damage per turn. You may use this feature up to 2x your Dexterity bonus.  You also gain resistance to Cold Damage. At level 17 there is no longer a limit on how many times you may use this ability.

Shadow Space

Beginning at 10th level, you conjure a portal to a demi-plane inside the Shadowfell. This space can store up to 1000lbs and keeps food from spoiling due to the cold nature of your shadows. A creature within your closed shadow space must make a DC 17 CON save, on a success they have 10 minutes before they begin to freeze, on a failure they have 1 minute before they start to freeze.

Spell Absorption

At 14th level, when you can see a spell being cast that you have to make a save for, you may use your reaction to summon a shadow portal in front of you. Make a DC 17 Dexterity save, on a success this portal absorbs the spell negating all effects and damage. On a failure the portal halves the damage of the spell. you may do this up to your Dexterity bonus per long rest. You also gain Immunity to Cold damage.