I am creating magic items for each god in my homebrew setting. These are based off of the Vestiges of Divergence from Critical Role, and they will increase in power as the campaign goes on and my PC's earn the god's favor. It is also possible that they may never unlock all the abilities. The last tier of the weapon is meant to make them powerful enough as a group to stand toe to toe with some of the most powerful creatures in the game.

I was looking through my most recent one for, Seething Wreath, and was wondering if the Blazing Ward ability seemed too strong or weak for level 16-17 play. As a reference of what I'm going for, I will include an item, Temptuous Ire, that I am happy with at the bottom. Any constructive feedback is welcome, and I am open to suggestions about other abilities as well. I really want to make these items something exciting and worth working on to get those higher level abilities. Here is the item:

Seething Wreath (Headgear)

Dormant

When you first attune to Seething Wreath, you are granted the following benefits in it's dormant state:

When Seething Wreath reaches an awakened state, it gains the following properties:

• Your Charisma score increases by 2, as does your maximum for that score.
• You are resistant to cold damage.
• You are immune to fire damage.
• You can now create 2 more Light Shards, for a total of 5. 

Exalted

When Seething Wreath reaches an exalted state, it gains the following properties:

• Your Charisma score increases by 3, as does your maximum for that score.
• When you hit a creature with one of your Light Shards, it bursts into a blinding light. They must make a DC 17 Constitution saving throw or be blinded until the end of their next turn.
• Blazing Ward: As an action, you can create a bright fiery sphere that surrounds you in a 10 foot radius once per long rest, shedding bright light in a 20-foot radius and dim light for an additional 20 feet. This effect lasts for one minute and ends if you fall unconscious or dismiss it as a bonus action. When a creature enters the area for the first time on a turn or starts its turn there, you can choose one of two effects:
  • The creature must make a DC 17 Dexterity saving throw, taking 4d8 fire damage on a failed save, or half as much damage on a successful one.
  • The creature is healed for 4d8 hit points. A creature can only benefit from this once until the start of your next turn.

Temptuous Ire (Longsword)

Dormant

Temptuous Ire is a +1 longsword. When you first attune to Temptuous Ire, you are granted the following benefits in it's dormant state:

When Temptuous Ire reaches an awakened state, it gains the following properties:

• You gain a +2 bonus to attack and damage rolls made with Temptuous Ire.
• Storm Aura. You emanate a stormy, magical aura while in your Tempest Rage. The aura extends 10 feet from you in every direction, but not through total cover. When this effect is activated, as a bonus action you can choose one other creature you can see in your aura. The target must make a DC 15 Dexterity saving throw. The target takes 2d6 lightning and 2d6 thunder damage on a failed save, or takes half as much damage on a successful one.
• You gain the ability to cast the Chain Lightning (save DC 17) through Temptuous Ire once per long rest long rest.

Exalted

When Temptuous Ire reaches an exalted state, it gains the following properties:

• You gain a +3 bonus to attack and damage rolls made with Temptuous Ire.
• You gain a flying speed of 40 feet.
• You gain an additional use of Tempest Rage, increased to a total of 3.
• You gain 2 charges of Chain Lightning. You can spend both charges to cast Storm of Vengeance (save DC 17). You regain both charges after a long rest.
• When you hit a creature with Static Smite, you now deal 8d6 lightning damage. You can choose to make the target roll a DC 17 Constitution saving throw or be stunned until the start of your next turn. After stunning a creature, you cannot do so again until you have completed a short rest.