Your biology is composed of a living alloy metal and flame,  granting you a semi-liquid, ever-shifting form. While you can maintain a stable humanoid shape, your body remains fundamentally amorphous, allowing it to flex, compress, and subtly reshape in ways solid creatures cannot.

This unique composition alters how the world interacts with you. Blows either go through you or are dispersed through your fluid form, and your molten nature grants you a natural affinity with heat and metal. However, your body is vulnerable to cold elements and you are slowed when submerged in water.

At level 5 you gain the action Vocal Imitation.

On the other hand Forgekin have their own language which is hidden in their forging and this is how they normally communicate. creatures can study this or have it as a language they have studied. you have the ability to use trinket message to use your language feature regularly.

Upon reaching 0 hp you're core drops to the ground and you become a Forgeling and move speed is reduced to 10ft and you have no actions you can take until you have 1d4 long rests which can be reduced per cast of healing magic on you to a minimum of one long rest in which case you return to small size and can become medium again after either a day or another long rest.

Your body cannot process normal food, and most conventional healing magic is less effective on you. You do not regain hit points from spending Hit Dice during a short rest. Instead, you must consume metal to restore your vitality.

As an action, you can consume a Small amount of nonmagical metal (such as a weapon, scrap, or similar material). When you do, you regain hit points equal to 1d4 per 5kg + your Constitution modifier, and you replenish any expended alloy-based abilities (if applicable). The DM may rule that larger or higher-quality metal increases this healing.

Additionally, your internal forge grants you slow, natural regeneration. At the start of your turn, if you have at least 1 hit point and have consumed metal within the last 24 hours, you regain hit points equal to your Proficiency Bonus. This regeneration ceases if you have not consumed metal recently or if you are reduced to 0 hit points.

Without access to metal, your body cannot properly repair itself—you gain no benefit from this trait and cannot regain hit points except through magical means.

as a reaction upon taking slashing damage, you can split as a reaction, creating two smaller versions of yourself.

• Medium → 2 Small → 4 Tiny (maximum of 4 bodies total).
• Each time you split, your current hit points are divided evenly among the 2 new bodies from the previous one.
• Each body occupies its own space and can move independently.

Diminished Strikes
Your weapons and attacks weaken as your mass is divided:

• At 2 bodies: your weapon damage is reduced by 1 damage die (e.g., 1d8 → 1d6).
• At 4 bodies: your weapon damage is reduced by 2 damage dice (minimum of 1D4 damage die).

Fragile Division

• If any one body is reduced to 0 hit points, it is destroyed, and the remaining bodies each take minor force damage (e.g., your Proficiency Bonus).
• Area effects affect all bodies individually.

Reforming

• If two or more bodies end their turn within 5 feet of each other, they can merge, combining their hit points (up to your maximum) and increasing size and mass accordingly.

Expending 1D4 HP you can create 5 kg up to 4D4 health for up to 20 kg of Ooze alloy or create Forgekin globules from level 5

you can shape and mould the Ooze Alloy into various items or use in most crafting recipes as a substitute for metals as you're Ooze alloys properties aren't set until the metal cools.  This usually takes a minute but depending on the amount of energy you put into it (the ratio of metal and you're fire magic) you can decrease it to 6 seconds or increase it to take an hour to allow mixing it into other metals to get newer properties of mixing or allow for more time to use special blacksmithing techniques.

The ability to create Forgekin globules unlocks at level 5

Forgekin globules act as amorphous magic material separate to the Forgekin itself and can be stored for later use, uses for these globules can include being used as a magic resource in magic items giving special actions like a burst of movement speed or increased power in a swing of a weapon. it can also be used in various items like small fire traps and other things as a magic resource usually involving some sort of fire or metal production based effect

Last but not least a common occupation for adventuring Forgekins is the role of the artificer and as such (up to DM discretion) they can use their metals when making an item to add one or more extra Forgekin based properties to them.

properties Forgekin Ooze alloy bonuses include but not limited to...

Fire resistance

a fire damage bonus (dice is based on weapon or item)

Alloy globules in or attached to items can have various effects and actions you can take while attuned to the item depending on its purpose,

this can vary dramatically from one use items like fire bombs and mines to magic items that produce flame effects that regain charges which usually will require attuenment.

Note: If you were to Consume Material using an item made with this trait you only get a 1D2 of healing per 5 kg of mass