When you choose this magical study at 2nd level, you learn the Shape Water cantrip. If you already know this cantrip, you learn a different mage cantrip of your choice. The cantrip doesn’t count against your number of cantrips known.
Frost mages stand apart from their colleagues, in that their chosen school of magic focuses on maintaining supreme control over the capabilities of their enemies. Mages who command frost perform chilling displays on the battlefield, rendering foes immobile as they bombard them with ice.
As a Frost Mage, you gain the following class features when you reach the specified Mage levels.
When you choose this magical study at 2nd level, you learn the Shape Water cantrip. If you already know this cantrip, you learn a different mage cantrip of your choice. The cantrip doesn’t count against your number of cantrips known.
You gain one of the following features of your choice:
Ice Barrier. You can weave the cold around yourself for protection. When you cast a spell of 1st level or higher that deals cold damage to a creature, you can simultaneously warp part of the spell’s magic to create an icy barrier on yourself that lasts until you finish a long rest. The barrier has hit points equal to twice your mage level plus your Intelligence modifier. Whenever you take damage, the barrier takes the damage instead. If the damage reduces the barrier to 0 hit points, you take any remaining damage.
When the barrier is reduced to 0 hit points, each creature within 10 feet of you has their speed reduced by 10 feet until the start of your next turn as the barrier bursts.
While the barrier has 0 hit points, it can’t absorb damage, but its magic remains. Whenever you cast a spell of 1st level or higher that deals cold damage, the barrier regains a number of hit points equal to twice the level of the spell. Once you create the barrier, you can’t create it again until you finish a long rest.
Water Elemental. You learn how to conjure a water elemental. It is friendly to you and your companions, and it obeys your commands. See the creature’s game statistics in the water elemental stat block.
In combat, the water elemental shares your initiative count, but it takes its turn immediately after yours. It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action to command it to take one of the actions in its stat block or the Dash, Disengage, or Help action.
If you target the water elemental with a spell that deals cold damage, it is considered immune to the damage and regains a number of hit points equal to it. You don’t need to roll to hit your elemental and it automatically fails any saving throw for it if you choose it.
At the end of a long rest, you can conjure a new water elemental. If you already have a water elemental from this feature, the first one immediately perishes.
Whenever a creature would take cold damage from one of your mage spells, its movement speed is reduced by 10 feet until the end of your next turn.
When a creature has its speed reduced in this way, you can spend one sorcery point: that creature must succeed on a Strength saving throw against your spell save DC or be restrained for 1 minute. If a creature lands a successful hit against the creature the conditions caused by Brain Freeze are removed.
Beginning at 14th level the creature becomes paralyzed instead of restrained.
You gain one of the following features, depending on your choice at 3rd level.
Ice Barrier. When a creature that you can see within 30 feet of you takes damage, you can use your reaction to cause your Ice Barrier to manifest around it and absorb the damage. If this damage reduces the barrier to 0 hit points, the barricaded creature takes any remaining damage. In addition, you can now spend sorcery points to cause the effect of Brain Freeze.
Water Elemental. Your water elemental changes into an ice elemental and gains the following additional benefits:
You can use your action to conjure up a ring of magical runes to invoke the deepest cold around a point you can choose within 60 feet. The ring has a 30-foot-radius and fills a 10-foot tall cylinder with frigid cold.
Creatures inside the area must succeed on a strength saving throw against your spell save DC or become paralyzed for up to 1 minute or until they take damage. If a creature’s body is fully inside the area the save is made with disadvantage. On a successful save a creature isn’t restrained.
Additionally creatures passing through the area with non-magical means have their movement speed halved until the end of their next turn after leaving the area. Additionally ranged attacks made through the area are made with disadvantage.
Once you use this feature, you can’t use it again until you finish a long rest.