Designing a Logia Devil Fruit Sheet
Logia Devil Fruits are one of the three types of devil fruit classifications, allowing their users to turn transform their body into a natural element, while also being able to create and control it. Logia type devil fruit powers are normally considered the rarest and strongest of the three types.
Logia Subtypes
Solid Logias, Liquid Logias, and Gaseous Logias are the three subtypes of logia devil fruits that defines a logia user's abilities and what element and state of matter they can transform into or use with their powers. All three of these subtypes are roughly equal in power, though some logia elements can be weaker than others on average.
Type: Solid Logia User
Solid logia devil fruit powers allow their users to transform themselves into a solid element, create solid objects out of that element, and transform materials into that element. For example, the Hie Hie no Mi, or ice logia power, allows its user to transform into ice that can break apart or reform without inflicting damage on the user. Additionally, the user can freeze just about any object, and can create weapons or structures out of ice. Other elements that solid logia fruits might specifically use are materials such as wood, stone, brick, glass, salt, and metal.
Type: Liquid Logia User
Liquid logia devil fruit powers allow their users to transform themselves into a liquid element, create liquid pools, waves, or fluid objects out of that element, and break down materials by using that element. For example, the Magu Magu no Mi, or magma logia power, allows it user to transform into magma that can morph into a puddle or mold into any fluid shape to avoid attacks. Additionally, the user can use the magma to melt down objects, create hell hounds out of magma, or produce volcanic eruptions. Other elements that liquid logia fruits might specifically use are materials such as mud, syrup, gasoline, blood, milk, wine, or a liquid chemical. Liquid fresh water or sea water cannot be used as a logia element.
Type: Gaseous Logia User
Gaseous logia devil fruit powers allow their users to transform themselves into a type of gas, plasma, or free-moving particle, and can use this element to create clouds, missiles, beams, or produce other various effects. For example, the Pika Pika no Mi, or light logia power, allows its user to disperse into light particles and reform at the speed of light. Additionally, the user can create explosive light beams, project themselves as a beam of light to move at unmatched speeds, and create various weapons out of light. Other elements that gaseous logia fruits might specifically use are wind, smoke, sand, helium, xenon, neon, propane, poison gas, fire, snow, and lightning.
Type: Darkness Logia User
The Yami Yami no Mi, or darkness logia, is such a unique and powerful devil fruit that it deserves its own subcategory. It can be considered one of the strongest, if not the strongest, devil fruit. Unlike other logias, its user cannot disperse into darkness or avoid physical attacks. However, it gives the user complete control over darkness that they can produce, which can consume any material or element. The specific stats and abilities of this power will be listed under "More Exmple Logia Sheets".
Logia Damage Type, Resistances, and Immunities
Logia users are provided with some of the greatest protection, agility, and damage out of all devil fruit types. Being able to disperse into their element, they can avoid just about any attack. And because they can transform into their element at any time, they can consistently deal a damage type based on their element.
Devil Fruit Feature: Logia Resistances and Immunities
Logia devil fruit users will almost immediately notice that they are immune to certain types of elemental damage and conditions, as their body composition is changed into their element. Additionally, all logia fruits aside from the Yami Yami no Mi, or darkness logia fruit, grant its user complete immunity to nonmagical bludgeoning, piercing, and slashing damage.
For example, an ice logia devil fruit will make its user immune to all physical damage and cold damage, as well as any conditions applied from cold environments or cold-based attacks. Working with your DM, decide which of the following features apply to you based on your devil fruit's power and nature.
Devil Fruit Feature: Logia Attacks
You can choose to deal a specific type of damage by replacing the damage type of your attacks and devil fruit spells with one that matches your power. If your devil fruit does not have a special elemental damage type to pick from, choose between bludgeoning, slashing, or piercing (based on how you use your powers).
For example, the Pika Pika no Mi, or light logia power, will allow its user to deal radiant damage with any spell, ranged, or melee attack made using its devil fruit powers. An ice logia power will grant its user the ability to use cold damage, a magma logia power will grant its user the ability to use fire damage, etc. This would also mean if you cast a spell using your devil fruit ability, such as fireball, you will replace the fire damage with the damage type corresponding to your devil fruit's nature (such as radiant damage for a Pika Pika no Mi user).
Logia Basic Skills
Every logia type devil fruit will have at least one ability or attack that can be used innately so long as the devil fruit user is not incapacitated or exposed to water or seastone. Elemental cantrips such as Firebolt work well for this purpose, as they can be used infinitely for little to no cost.
Logia Elemental Form
As a logia user, you can channel your devil fruit powers through your body to enter an elemental form, fully altering your body composition to match your logia material. You can enter this form as an action on your turn.
While in your elemental form, unless you are using the Yami Yami no Mi devil fruit, you gain the following benefits:
You gain a +2 bonus to AC.
You have advantage on Dexterity checks and Dexterity saving throws.
You can move through the space of another creature, and it doesn't count as difficult terrain. If you end your turn in another creature's space, you are shunted to the last unoccupied space you occupied, and you take 1d8 force damage.
You choose which equipment you are holding transforms into your element and travels with you normally. Worn equipment functions as usual, but benefits from your resistances and immunities and attacks that normally phase through you will also phase through your equipment as if it is a part of your body.
Your elemental form lasts for a number of minutes equal to half your character level (rounded up). It ends early if you are knocked unconscious, become incapacitated by seastone or water or end it as a bonus action.
You can enter this form a number of times equal to your Proficiency bonus. You regain all expended uses of this feature when you complete a long rest.
Depending on your logia subtype, you also transform into a mist, pool, or mass of solid material matching your element for the duration of the your elemental form, gaining these additional abilities:
Solid Form
As a bonus action on your turn, shattering into solid pieces of your logia element and reforming, you teleport up to 30 feet to an unoccupied space that you can see.
Liquid Form
You can spend 5 feet to transform into your liquid element and move into the small cracks of a solid surface and reform in a puddle, reappearing on a spot on the same surface up to 30 feet away from you that you dont need to be able to see. You can use this transportation ability once per round for the duration.
Gaseous Form.
Still in the shape of your original form, you become a misty cloud of particles made of your element for the duration, making your only method of movement a flying speed equal to your movement speed. You can pass through small holes, narrow openings, and even mere cracks. You remain hovering in the air even when stunned or otherwise Incapacitated, unless by seastone or water.
Design Tips
Logia powers can be viewed as paramecia powers with far greater abilities, immunities, and spells. The example logia sheets provided here and later will show designs for every Logia Devil Fruit listed under "Devil Fruit Generation." If you wish to create custom Logia devil fruits based on different elements, use these sheets as a template.
The example sheet below shows an early design idea for the Moku Moku no Mi using logia immunities and resistances as well as basic skills.
Example: Moku Moku no Mi (Smoke)
Devil Fruit, Very Rare
Type. Gaseous Logia
Fruit appearance. Puffy white melon with cloud-like swirls.
Description. Allows its user to create, control, and transform into smoke at will.
Sea Weakness. You are weak to water and seastone.
Logia Immunity. You are immune to bludgeoning, piercing, and slashing from nonmagical attacks, as physical objects pass through your smoke body. Additionally, you can see normally through smoke, cloud, and fog-like effects that cause an area to become lightly or heavily obscured.
Elemental Form. You can use the "Logia Elemental Form" feature listed under "Designing a Logia Devil Fruit Sheet".
White Blow. Your limbs extend, connected by smoke. You can use the Mage Hand cantrip. Additionally, when you make a melee attack on your turn, your reach for it is 30 feet greater than normal.
Logia Spells, Skills and Awakening
Similar to creating a paramecia devil fruit power, designing and deciding which spells and skills which can be used with a devil fruit can be tricky at first. Hopefully, after following these steps, choosing paramecia devil fruit spells will become a little more intuitive.
Also be sure to refer back to "Designing a Devil Fruit Sheet with Steps" under step 4 for more examples and an explanation on devil fruit charges and which spell levels to choose from.
To decide which spells to choose from, make sure you keep their spell level beneath the "highest spell level" equal to or lower than the number decided by the devil fruit's rarity. The spell you choose can be from any 5e class spell list. Next, select at least 1 or more spells within that range and modify them as needed. Remember to stick to the rules of paramecia subtypes in order to decide what these spells will be allowed to target, such as "self only" for body enhancers.
A good example for this might be for a Mera Mera no Mi (fire) logia devil fruit user to be able to cast Burning Hands (1 charge) and Fireball (3 charges), representing how its user can use skills involving bursts of fire. Additionally, an awakening ability might be a much higher level spell than can be used once per day, even bypassing the spell level limit for that devil fruit.
Here is another more in-depth example below still using the Moku Moku no Mi, a very rare type devil fruit, as a template to show which type of spells and awakening ability might be appropriate to use.
Spells (Smoke Plumes). This devil fruit power has 13 charges. Using your ability to produce smoke, you can expend 1 or more of its charges to cast one of the following spells from it without needing to expend material components: Fog Cloud (1 charge), Misty Step (2 charges), Gaseous Form (3 charges), Stinking Cloud (3 charges), Cloudkill (5 charges), Investiture of Wind (6 charges), Wind Walk (6 charges). The devil fruit regains expended charges daily at dawn.
Awakening (Explosive Plume). Once you've awakened your power, you can use an action to cast Incendiary Cloud without expending any charges or material components. You can’t use this feature again for another 24 hours.
Design Tips
There are a wide variety of official D&D resources and books, including the official D&D Dungeon Master's Guide, that provide a wide variety of spells you can use for the purpose of devil fruit creation. Keep logia spells in line with their logia element (e.g. Mera Mera no Mi logia can cast burning hands, fireball, etc.). A very rare logia should at the very least on par with a 7th-level or higher spell, while a legendary logia awakening should be on par with a 9th-level spell. If you are having trouble finding a fitting spell for a certain logia element, feel free to alter existing spells to fit the devil fruit's abilities.