I have a player interested in playing a fire genasi character as either a warlock or barbarian, and they want to have a unique subclass. We've come up with a subclass concept and have hopefully done a good job balancing it. This post is concerned with the balance of a barbarian subclass.
Path of the Firebird
Barbarians who follow the Path of the Firebird believe in the power of the mythical firebird, praying for its blessing and gaining powers in return. When they rage, the burning power of this fiery creature incinerates their opponents while soothing their wounds. They are able to commune with this elemental creature of fire and it may burn away the veil that hides the hidden truths of the multiverse.
Ignite: At 3rd level, you gain the ability to start fires with a touch. As an action, you can magically ignite a flammable object you touch with your hand—an object such as a torch, a piece of tinder, or the hem of drapes.
Mantle of Flame: Starting at 3rd level, you can unleash the fire that blazes within you. While you are raging, you magically wreathe yourself in swirling fire and your eyes glow like hot coals. For the duration, you gain the following additional benefits:
- You shed bright light in a 30-foot radius and dim light for an additional 30 feet.
- The first time in a round that a creature hits you with a melee attack and is within 5 feet of you, it takes fire damage equal to your Constitution modifier.
- On your turn, the first time that you hit a creature with a melee attack, you can cause additional fire damage equal to your Constitution modifier.
Touched by Fire: The firebird has touched your soul and you have become one with its fire. At 6th level, you may choose to have resistance to fire damage or advantage on saving throws against fire-based effects such as a fireball or breath weapon. You make this choice when you gain this feature, and can change it when you gain a level.
Commune with the Firebird: At 10th level, you can cast the commune spell, but only as a ritual and using a large outdoor fire as the material component. When you do so, a spiritual version of the firebird appears to you in the flames to convey the information you seek. You are the only one that can see and hear the firebird spirit.
A Soul Alight: At 14th level, your bond with the firebird increases and your Mantle of Flame is now empowered to grant even more destruction. All of your attacks can now inflict fire damage equal to your Constitution modifier, and all creatures who make successful melee attacks against you experience this same fire damage as well. In addition, the flames swirling around you grant you temporary hit points at the start of each of your turns equal to your Constitution modifier.
Ignite is pretty much a nothing burger from a balance standpoint. Prestidigitation does the same thing with a range of 10 feet, has a bunch of other functionality, and a caster doesn't have to wait until 3rd level to get it.
Mantle of Flame at 3rd level will likely only do 2 or 3 points of damage, depending on how your table handles rolling for stats. Adding 2 points to the first weapon attack as fire damage is utterly insignificant compared to Storm Herald's Storm Aura: Desert which does 2 points of damage to everything within 10 feet...that's as much as 48 points of damage per round against medium sized targets with no chance to miss. Battlerager gets a bonus action attack which could easily out DPR Mantle, and Zealot does even more damage with an extra d6 plus half class level on their first attack.
Now, the other half of Mantle is opponents take fire damage when they hit the barbarian. Here's where I think Mantle will begin to equal Zealot's DPR with a single opponent, and pull ahead with several. Storm Herald still has greater damage output across the board as it's not reliant on an enemy hitting the barbarian and has a comparatively massive range.
Touched by Flame's 6th level resistance option is inferior to Storm Herald as it doesn't have the flexibility of providing different kinds of resistances (not to mention breathing underwater, etc). I make up for this lack of flexibility in allowing the advantage on saves option. No other barbarian subclass gets advantage on saves versus a damage type, but Berserker gets straight up immunity to the Charmed and Frightened conditions while raging, which I think is a more powerful feature. Additionally, baseline barbarians have Danger Sense (advantage on DEX saves), so this second option will be redundant in all but 4 spells.
The commune feature is similar to the 10th level Totem Warrior feature commune with nature. I don't think either of these spells is particularly useful considering the ritual casting requirement, but I feel that each has an opportunity to shine given the right situation.
A Soul Alight, this subclass's 14th level capstone feature (I've assumed CON was maxed by this point), allows the barbarian to add up to an extra 5 points of fire damage to each attack and all enemies would suffer up to 5 points of fire damage every time they hit the barbarian. At 14th level, a barbarian normally only gets two attacks, so at most they'll be dealing 10 extra fire damage per round. If their CON is maxed, this portion of the feature would allow for more damage output than other classes, but I think that output is small enough that it doesn't come close to being overpowered.
As for the other portion of Mantle where enemies take damage from hitting the barbarian, I can foresee some situations where this would pull ahead of the Storm Herald's Storm Aura, particularly against creatures with many attacks like a hydra, but even then I don't think this would be broken. Both Berserker and Storm Herald can use a reaction to do damage when an enemy hits them (a regular attack and fire damage for half of class level, respectively), and one on one, both of these options would do more damage. For perspective, Mantle's up to 5 points of fire damage per hit taken happens at a level where enemies have hundreds of hit points and almost 500 monsters have resistance or immunity to fire.
In short, I don't think this subclass in unbalanced but getting more input certainly isn't going to hurt.
Is this barbarian Path of the Firebird subclass balanced compared to other barbarian subclasses?