Base Class: Barbarian
Storm heralds are typically elite champions who train alongside druids, rangers, and others sworn to protect nature. Other storm heralds hone their craft in lodges in regions wracked by storms, in the frozen reaches at the world’s end, or deep in the hottest deserts.
Storm Aura
Starting at 3rd level, you emanate a stormy, magical aura while you rage. The aura extends 10 feet from you in every direction, but not through total cover.
Your aura has an effect while you are under the effect of your rage. Choose desert, sea, or tundra. Your aura’s effect depends on that chosen environment, as detailed below. You can change your environment choice whenever you gain a level in this class.
If your aura’s effects require a saving throw, the DC equals 8 + your proficiency bonus + your Constitution modifier.
Desert
When this effect is activated, all hostile creatures in your aura take fire damage equal to half your Barbarian level (minimum of 1). Additionally, when this effect is activated or when you use your bonus action on subsequent turns, you channel the storm into your weapon until the start of your next turn. When you hit with attack action, the target takes and additional 1d6 fire damage. The damage increases when you reach certain levels in this class, increasing to 2d6 at 5th level, 3d6 at 10th level, 4d6 at 15th level, and 5d6 at 20th level.
Sea
When this effect is activated, all hostile creatures in your aura take lightning damage equal to half your Barbarian level (minimum of 1). Additionally, when this effect is activated or when you use your bonus action on subsequent turns, you channel the storm into your weapon until the start of your next turn. When you hit with attack action, the target takes and additional 1d6 lightning damage. The damage increases when you reach certain levels in this class, increasing to 2d6 at 5th level, 3d6 at 10th level, 4d6 at 15th level, and 5d6 at 20th level.
Tundra
When this effect is activated, all hostile creatures in your aura take cold damage equal to half your Barbarian level (minimum of 1). Additionally, when this effect is activated or when you use your bonus action on subsequent turns, you channel the storm into your weapon until the start of your next turn. When you hit with attack action, the target takes and additional 1d6 cold damage. The damage increases when you reach certain levels in this class, increasing to 2d6 at 5th level, 3d6 at 10th level, 4d6 at 15th level, and 5d6 at 20th level.
Storm Soul
Desert
You gain resistance to fire damage, and you don’t suffer the effects of extreme heat, as described in the Dungeon Master’s Guide. Moreover, as an action, you can touch a flammable object that isn’t being worn or carried by anyone else and set it on fire.
Sea
You gain resistance to lightning damage, and you can breathe underwater. You also gain a swimming speed of 30 feet.
Tundra
You gain resistance to cold damage, and you don’t suffer the effects of extreme cold, as described in the Dungeon Master’s Guide. Moreover, as an action, you can touch water and turn a 5-foot cube of it into ice, which melts after 1 minute. This action fails if a creature is in the cube.
Shielding Storm
At 10th level, you learn to use your mastery of the storm to protect others. Each creature of your choice has the damage resistance you gained from the Storm Soul feature while the creature is in your Storm Aura.
Raging Storm
At 14th level, the power of the storm you channel grows mightier, lashing out at your foes. The effect is based on the environment you chose for your Storm Aura.
Desert
Immediately after a creature in your aura hits you with an attack, you can use your reaction to force that creature to make a Dexterity saving throw. On a failed save, the creature takes fire damage equal to half your barbarian level.
Sea
When you hit a creature in your aura with an attack, you can use your reaction to force that creature to make a Strength saving throw. On a failed save, the creature is knocked prone, as if struck by a wave.
Tundra
Whenever the effect of your Storm Aura is activated, you can choose one creature you can see in the aura. That creature must succeed on a Strength saving throw, or its speed is reduced to 0 until the start of your next turn, as magical frost covers it.