School of Evocation: Mastery of Frost

Upon entering the School of Evocation, where the utilization of all the elements is taught, you opted to spend your time focusing on just the element of frost. Specializing in the manipulation of water, you've become an expert in its applications. Some Mastery of Frost Wizards spend their time creating water in underprivileged communities, some may embark with expeditionary forces into frigid climes as a resource for manipulating the elements and others may use their expertise as a means to destroy their enemies in the name of a king or for their own ambition. 

Glacial Savant

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

Bone Chill

Beginning at 2nd level, the coldness of your spells seeps into the bodies of your enemies making them slow and lethargic. When you cast a spell that deals cold damage, you can target creatures affected that you can see up to 1+ the spell's level and reduce their speed by half until the end of their next turn. You can do this a number of times equal to your spell casting ability modifier per day. Additionally, you learn either the Frostbite or Ray of Frost cantrip and it doesn't count against the number of cantrips you can know. 

Ice Armor

Starting at 6th level, you learn the Armor of Agathys spell and its protective shell is even harder to pierce. is When you cast Armor of Agathys, you gain extra temporary hit points equal to your Wizard level when you cast it. Additionally, when you affect creature(s) you can see with a spell that deals cold damage, you can choose to expend your temporary hit points to deal extra cold damage to one of the affected creatures equal to half the total temporary hit points rounded down. 

Frost Mastery

Beginning at 10th level, your proficiency with manipulating the cold has made ice benign to you and deadly to your foes. You gain resistance to cold damage, your speed cannot be reduced by icy terrain and when you affect creature(s) you can see with a spell that deals cold damage and requires a saving throw, if they fail by more than 5, their speed becomes zero and they're grappled. The affected target may spend their action to break free or, at the end of each of their turn(s), the target(s) may repeat the saving throw against your spell save DC.

Icy Incubation

Starting at 14th level, you can create a shell of ice to protect you and treat your wounds. You gain the warlock invocation Tomb of Levistus, it can be used once per short rest and it gains the following extra effects when used:

- This ability benefits from Ice Armor in that you gain extra temporary hit points equal to your wizard level.

- The effect ends at the beginning of your next turn and you heal for half of the total temporary hit points left over at the end of the effect.

- You can use this a number of times equal to your spell casting ability modifier but, each time you do, the amount of temporary hit points you gain is reduced by half rounded down (excluding the bonus from Icy Armor). Once you take a long rest, the effect of diminishing returns resets.