Fire, Blood and Steel

As the fist of the drunken man impacted the tiny halfling womans face, he screamed in agony as his knuckles broke against her cheeks, who had become hard as steel in the last possible moment.

A huge goliath smiles as the guards exclaim that he is unarmed. He holds out both of his hands, and his blood from a greataxe in his grip, who glows with a bright orange edge

A tiefling with black steel gauntlets and boots rockets through the air at an incredible speed,

You have gained a magical infused type of steel in your veins, granting you powers beyond any normal soldier. This steel could have gotten into your body through the wounds you have sustained on the battlefield, and fused itself with your natural magic. maybe it was granted to you by a god or an unknown magical entity. Whatever the case, you now have liquid metal floating through your body, and a fire burns in your soul.

Blood, Steel and Fire

When you choose this subclass at level 3, you gain the following benefits:
Weapon creation: you gain the ability to create melee weapons from your blood as a free action, this weapon can take on any shape you want every time you summon it. should you have the dual wielder feat, you gain the ability to summon two weapons instead of one. If you drop your weapon, it becomes a swirling river of metallic liquid that returns to your body. this happens automatically if you are incapacitated

Steel Skin: Your skin can harden on impact with a hazard. You gain unarmored defense = 10+DEX+CON

Fire Soul: the fire that burns in your soul lets you heat up your weapons. You gain the ability to heat up your weapon as a bonus action, adding 1d4  extra points of fire damage to it. This damage changes to 1d6 at level 6, 1d8 at level 10 and 1d10 at level 17.

Spellcasting

You gain the ability to ignite some of your liquid metal. You gain the Firebolt cantrip, and the spells Burning Hands, Aganazzar’s Scorcher and Scorching ray. Constitution is your spellcasting modifier.

Spellcasting Ability

Intelligence is your spellcasting ability for your Fire spells. You use your constitution whenever a spell refers to your spellcasting ability. In addition, you use your constitution modifier when setting the saving throw DC for a fire spell you cast and when making an attack roll with one.

Spell save DC = 8 + your proficiency bonus + your Intelligence modifier

Spell attack modifier = your proficiency bonus + your Intelligence modifier

Advanced Metal

Starting at 7th level, your body can utilize the steel in your veins. You gain Expertise in Athletic checks made to lift, hold up or push objects. If you dont already have it, you gain powerful build

Your strength score increases by +1, to a maximum of 22

In addition your weapons have absorbed parts of your fiery soul, making your melee weapons magical for the purpose of overcoming resistances and immunities 

You gain immunity to effects that extreme cold or hot weather can have on you

 

Intense heat

Starting at 10th level, the inner heat that burns in your heart and soul is becoming intense enough to rival fire elementals. You gain resistance to fire damage, if you already have resistance, it becomes immunity

As a bonus action you can encase your legs and arms in your bloody steel, becoming half of a steel champion. This transformation lasts for one hour and can be activated a number of times equal your CON modifier, you can revert back as a bonus action. You automatically revert to your normal form if you fall unconscious, drop to 0 hit points, or die. Your transformations reset after a long rest

While transformed, if you use your action to cast a cantrip, you can make one melee attack as a bonus action. 

In addition you gain a flying speed of 60 feet, with the ability to hover, as jets of fire shoot out of your armored legs and hands. While flying you can not have a weapon in your hand, as it will throw you off balance, you can hover and still have a weapon.

Being of Steel

Starting at 15th level, you gain resistance to bludgeoning, piercing and slashing damage as well as immunity to being poisoned and diseases  

Champion of fire, blood and steel

At 18th level, you attain the pinnacle of resilience in battle. you gain the ability to transform your body almost completely into steel, the transformation lasts for 10 minutes. While the transformation lasts you gain the additional benefits. You can transform as a bonus action. And once you have done it, you can not do so again until your next long rest

Your gain resistance to all forms of damage except force and psychic

Your strength score increases to 24

You are impossible to knock over, you gain immunity to being knocked prone

When you use your action to cast a spell, you can make a melee attack as a bonus action

note: this transformation does not stack with the flying transformation because you become very heavy