Goblin Devil Magic

North of the Emerald Kingdoms lies the island of Jauku, home to the Yokai and a city of the infernal creatures known as Oni. Yokai are said to pervade the world around the Emerald Kingdom in the Border Ethereal, as this is the layer of reality these spirits thrive most in. Yet they cling to the physical realm in hopes of bringing their unique individual ambitions and desires to life in the material world. Not all Yokai are as demonic and troublesome as their cousins, the Oni, but their magic is nonetheless drawn from similar powers to utilize the near-Ethereal and their own connection to realms of shadow, with their own extremely unique arcane systems in their respective languages. Often, the acts performed as somatic components are insulting gestures, or biting the heads off living insects, and the verbal components are snarls in the guttural Infernal tongue, or insults in other languages. Essentially, the Goblin Devil Magic is obscene to all but the Oni and Yokai themselves, and it is distinct, without question.

Goblin Devil Magic itself is a dark arts system that encompasses a vast variety of magical capabilities. Most particularly, they are shapeshifters with the capability to inflict terror and madness on weaker minds, and their ability to inflict awful and terrible curses is by far their greatest menace. They often control and debuff their foes in terrible ways, and inflict great magical harm. When these spellcasters are sent out into the world, they are almost always females, and they are almost always on some mission for a greater matron of her clan. The few males who know these secrets are often awful warlords with a chaotic hold on their own territory.

Oni's Bearing

1st-level Goblin Devil Magic feature

At 1st-level, you learn to simulate the necessary posture, acts, and attitude to cast your terrible magic spells. This bestows you with a sort of "magical state" you can enter into as a type of trance. As a bonus action, you go into a wild-eyed, trance-like state and gain the following benefits:
Oni's Might. You temporarily increase your Strength score by 2, to a maximum of 20, and you have advantage on Strength checks and saving throws for the duration.
Shifting Form. As an action while in this state, you can transform your body into that of any animal of challenge rating 1/4 or less for a number of rounds equal to your Charisma modifier, as if you possessed the Wild Shape class feature of the Druid. When this duration ends, you cannot transform this way again until you enter this state again.
Spell Mischief. When you cast a spell or cantrip in this state, you may roll 1d4 and add that total to any spell attack roll or damage roll of the spell.
These benefits last for a number of minutes equal to your Charisma modifier (minimum 1), and you can use this feature once before you must finish a short rest to use it again.

Additionally, you learn the Vicious Mockery cantrip.

Expanded Spell List

1st-level Goblin Devil Magic feature

Expanded Spell List

Goblin Devil Magic lets you choose from an expanded list of spells when you learn a warlock spell. The following spells are added to the warlock spell list for you.

Goblin Devil Magic Expanded Spells

Goblin-Devil Terror

6th-level Goblin Devil Magic feature

At 6th level, you learn to utilize terror as a fundamental magical effect that you use easily with demonic masks. You gain proficiency in Intimidation and you double your proficiency bonus with all Intimidation rolls. Additionally, you learn the Fear spell, and you can cast this spell without components if you are wearing a mask with a demonic visage.

Horrid Vulgarity

10th-level Goblin Devil Magic feature

At 10th level, you have ascertained the mysterious truths of the Oni and Yokai's magical prowess, and you understand the principles of energetic exchange that occur when you appropriately insult and offend another person. With this knowledge comes the ability to harness the shock and emotion of your enemies to your advantage and even inflict "insanity" upon other minds. Whenever you cast a spell using Warlock spell slots that deals damage or has a condition effect descriptor (i.e. Sleep) or also a debuff effect descriptor, you can choose one target of that spell and cast the Vicious Mockery cantrip on it as part of the action of casting that spell. For instance, if you cast the Cause Fear spell, you can choose one target of that spell and that target has Vicious Mockery cast on it as part of that action.

Additionally, you learn the Phantasmal Force spell. If you have cast Vicious Mockery since the beginning of your last turn, you can then cast Phantasmal Force as a bonus action until the end of your current turn. When you cast this spell or the Phantasmal Killer spell while in your Oni's Bearing state, you add your Charisma modifier to the psychic damage dealt by those spells. 

Unclean Blasphemies

14th-level Goblin Devil Magic feature

At 14th level, you have come to understand that Goblin Devil Magic thrives most on corruption and perversion of the most sacred traditions and practices. It is the outrage of the spirits of the world that one might dare such corruption which creates a sort of "emotional feedback loop" in the energy of your magic, making some of your spells much stronger in areas of corruption. You learn the Hallow spell, you can cast it without material components, and whenever you are in the area of a Hallow spell you have cast, you gain a +2 bonus to spell attack rolls and spells you cast have their save DC increase by 2.

Additionally, your patron now sees you as equal in footing to their own inner corruption, and as such, they allow you to learn the greatest curses the Oni know: the Kodoku, the Kotoribako, and the curse that lies beyond death, the making of many Yokai, the Jaakuna Noroi. You gain the following benefits:
- You learn the Magic Jar spell and can cast it by expending any level of your Mystic Arcanum feature.
- You learn the Circle of Death spell, which you may ritually cast in any area you have cast the Hallow spell in, and to successfully cast this, you must have the remains of any humanoid creature in a wooden box. The effect of the spell does not take place upon completion of the ritual, but rather whenever a creature takes any action to open the box, the effect triggers with the box's space as the origin space. You can also cast this spell by expending any level of your Mystic Arcanum feature.
- When a creature you can see dies, you may use an action to attempt to turn that soul into a corrupted Yokai instead of moving on to an afterlife, and you roll a d20. On a roll of 11 or higher, the deceased creature becomes your choice of a Ghoul or a Ghast in a process that takes 1 minute. These creatures are not under your service or otherwise compelled to obey you in any way as a result of this feature alone.