Thoughts on homebrew warlock subclass ability

[Ttttttt]

Howdy,
I'm currently designing a warlock subclass based on the idea of chaos for one of my players. This is the first time I've ever designed a subclass (or character rule) and was wondering to everyone if it sounds good or if there are any changes that I can make to improve it. If there are any ideas you have let me know.
My player wanted an ability to work with a brand that his characters would have on his chest as a part of making a pact with his entity.

He also wanted an excuse not to wear armor so this is what I came up with.

Thanks!


Castigation Brand

At 1st level, your body is marked by a brand of chaos. This Castigation Brand can appear in many different ways but doesn’t disappear until your pact is over.

As a bonus action, you can expend a spell slot of any level to activate the Castigation Brand, allowing yourself to use chaos as fuel. When activated, the Castigation Brand allows you to use chaos as fuel to enhance your abilities but may cause your spells to become uncontrollable.

When you expend this spell slot, you gain a number of Chaos Fuel Points equal to the level of the spell slot expended. This chaos fuel can be burned to enhance your spells. When you cast a spell of 1st level or higher (that deals damage) or Eldritch Blast, you may expend any number of chaos fuel points you have to increase the damage by the spell by 2d6 of the same damage type dealt by the spell.

When you activate the brand, your AC also increases. This increase is equal to 14 + your proficiency bonus. Your AC does not increase if you have any armor equipped but your AC may be further increased through the means of magical items.

The brand stays activated until you burn all of your Chaos Fuel and cannot be activated if you are wearing armor. When you burn all of your Chaos Fuel your brand goes into a dormant state. Your AC bonus stays increased until your take a short or long rest, where afterward it then reverts back to normal.

There is no limit on the number of times you can fuel your brand per day excluding the spell slot limitations.

[Amnestic]

You probably want to adjust the wording on the AC stuff - I understand it, but the way it's worded is that it increases your AC by 14+Prof Bonus (meaning the total calculation would be 10+Dex+14+Profbonus), instead of letting you set your AC to 14+ProfBonus.

I'm concerned that it makes it pretty sweet as a dip multiclass option. You may want to change the wording to sacrifice a "warlock spell slot" or "pact magic spell slot" rather than any spell slot.

The damage, as written, also applies to an entire spell, rather than one target of it. So for instance if I cast Fireball after sacrificing another 3rd level spell slot I'd be doing 8d8+6d6 fire damage. While that's less damage overall than two fireballs, perhaps, it's also far more nova-efficient. Destroying enemies over one turn is better than destroying enemies over two turns, after all, and it makes you far more incentivised to combo-wombo it with AoE spells than single target spells.

Also since Magic Missile is a guaranteed hit spell (save for Shield shenanigans) this can drastically up guaranteed damage. Sacrifice a high level spell slot->cast level 1 magic missile->Guaranteed nuke, no save, no attack roll. Again, this is mitigated somewhat by only letting you sacrifice warlock spell slots.

[Greywander]

Hmm, it doesn't say anything about how your spells might become uncontrollable. What about something like this instead?

As a bonus action, you can activate your Castigation Brand to gain an additional pact magic slot, which must be used while the brand is active or else it is lost. When you activate the brand, you also immediately gain the benefits of the Mage Armor spell, which lasts for the spell's normal duration. The power of your brand is unpredictable; roll on the following table to see which effect your brand triggers. This effect applies to spells cast by those within 60 feet of you, or targeting anyone within 60 feet of you. Your brand remains active for 1 minute.

1. Spells cast near you become more powerful. Affected spells of 1st level or higher have their damage increased by 2d6, and healing increased by 1d6.
2. Spells cast near you become weaker. Affected spells have their damage or healing halved.
3. Spells cast near you heal instead of harm, and harm instead of heal. Affected spells will restore hit points equal to half the damage that would have been dealt, or deal damage equal to the amount that would have been healed.
4. Spells cast near you are redirected toward you. Affected spells will instead target you or your location.
5. Spells cast near you are reflected back on the caster. Affected spells will instead target the caster or their location.
6. Spells cast near you are delayed. Affected spells will take effect on the following round after the spell was cast.
7. Spells cast near you experience dramatic fluctuations. Affected spells of 1st level or higher have their spell level determined by rolling a d10, regardless of the level of spell slot that was used to cast the spell.
8. You tame the chaotic energy of your brand. You can choose which effect from this table is activated by your brand.

There is no limit on the number of times you can activate your brand.