AG's Boon of the Frost Monarch

You have immunity to Cold damage. Additionally, if you would take more than 25 Cold damage from any single source, you become surrounded by 15ft of sheer and brutal cold. While in this state, you benefit from the following effects.

• Creatures of your choice within the effect must spend 4ft of movement for every 1ft they move within the area unless that movement brings them closer to you.
• Attack rolls of your choice that hit within the area either deal an additional 5 cold damage, or have their damage reduced by 5.
• As a part of the bonus action you use to maintain this effect, you may force creatures which are not resistant or immune to cold damage to make a constitution saving throw against your spell save DC or 17. On a failed save, they gain a level of exhaustion.
• You must use your bonus action to maintain this effect, and it cannot be activated again for 5 minutes once deactivated. The effect ends automatically after 1 minute.