Wispy flames wreathe your body for the duration, shedding Bright Light in a 10-foot radius and Dim Light for an additional 10 feet. The flames provide you with a warm shield or a chill shield, as you choose. The warm shield grants you Resistance to Cold damage, and the chill shield grants you Resistance to Fire damage. In addition, whenever a creature within 5 feet of you hits you with a melee attack roll, the shield erupts with flame. The attacker takes 2d8 Fire damage from a warm shield or 2d8 Cold damage from a chill shield.
RollQuest ships the D&D 2024 SRD as a content pack, on a 5e character sheet that does the maths - roll from the sheet and let the numbers work themselves out. Free to start.