The Frenzied Flame

The Frenzied Flame, in a way, the rejection of order, and the rejection of life.

However the Demon lord you make this pact with does not offer this way cause of haltered for life, but instead trough the Philocaly, that life itself was a mistake, the realisation that life will always lead to suffering, and the desire to make that suffering stop. 

No matter how many good deeds are done by Clerics, and no matter how many people are punished by Paladins for there crimes. The suffering could not be undone.
The happiness of many does not outweigh the pain of one, and so the world must burn. 

Individuals who share this Philocaly are targeted by the Demon lord, to become vessels to his flame. 

Expanded Spell List

1st-level Frenzied Flame feature. 

You unlock the following spells:

Frenzied Burst at level 1

Flame of Frenzy and Howl of Madness at level 2

Frenzied Embrace and Fireball at level 5

Nihilist Vessel

1st-level Frenzied feature

Your patron gifts you a magical vessel that grants you a measure of his power. The vessel is a Tiny object, and you can use it as a spellcasting focus for your warlock spells. You decide what the object is, or you can determine what it is randomly by rolling on the table.

Nihilist Vessel

While you are touching the vessel, you can use it in the following ways:

Nihilist Wrath. Once during each of your turns when you hit with an attack roll, you can deal extra damage to the target equal to your proficiency bonus. The type of this damage is Fire.

The vessel’s AC equals your spell save DC. Its hit points equal your warlock level plus your proficiency bonus, and it is immune to poison and psychic damage.

If the vessel is destroyed or you lose it, you can perform a 1-hour ceremony to receive a replacement from your patron. This ceremony can be performed during a short or long rest, and the previous vessel is destroyed if it still exists. The vessel vanishes in a flare of elemental power when you die.

Nihilist Wrath

Nihilist Wrath. Once during each of your turns when you hit with an attack roll, you can deal extra damage to the target equal to your proficiency bonus. The type of this damage is Fire.

Destructive Madness

At 6th level, your connection to the Frenzy has become more potent. When a enemy gets affected by the Madness condition, instead of them being Stunned, they are instead Paralyzed until the end of there next turn.

You also gain Resistance to fire damage, if you already have Resistance to fire damage, you instead gain fire Immunity.

Frenzied mind

10th-level Frenzied flame feature

When a enemy makes a wisdom saving throw to resist the affects of Madness, you can chose to force them to make the saving throw, by having to make the same saving throw yourself.

Limited Wish

14th-level Frenzied flame feature

As an action, you can speak your desire to your Frenzied Patron, requesting the effect of one spell that is 6th level or lower and has a casting time of 1 action. The spell can be from any class’s spell list, and you don’t need to meet the requirements in that spell, including costly components; the spell simply takes effect as part of this action.

Once you use this feature, you can’t use it again until you finish 1d4 long rests.