Everfrost Shawl

You whisper a short plea to your deity. When the orison is over, you graze a weapon against a piece of your armor. A long mantle in different shades of white and blue begins to cover your back – it weighs nothing and is incorporeal, but you can feel it's there through unexplainable divine connection. In the serape, one can distinguish some dreadful shapes of otherworldly humanoid beings, victims or preys of the caster and creatures around him. After it materializes, you gain an aura of frost and ice which damages your enemies in a 10-feet-radius sphere centered on you. Every enemy creature that starts its turn inside the sphere or enters it must make a Constitution saving throw. It takes 3d6 cold damage on a failed save and half as much on a successful one. If it doesn't leave the sphere or enters it again, it must make the same saving throw on the start of its next turn.

Furthermore, your melee weapon attacks deal additional 1d8 + 1 cold damage if they connect. If the creature you hit with your weapon is wearing any armor, its hems and joints become covered in ice and metal elements display first signs of brittleness. That creature receives −2 penalty to AC until it leaves the hoarfrost zone of your magical aura or the spell ends.  

You can sacrifice an action on your turn to use your Channel Divinity while coated in the aura of Everfrost Shawl. When you do that, with a thunderous roar, you magically shove back every creature in a radius of 5 feet from you. Every Large creature or smaller must make a Dexterity saving throw or else is pushed 10 feet away from your location. A Huge creature or bigger is not affected. The mantle dissipates forthwith and the spell ends. 

At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the aura deals additional 1d10 cold damage and the damage of your melee weapon attacks increase by 1d6 + 1 for every slot above 4th.