What is Cold Iron actually? [closed]

It came up in Dresden Files, but is not limited to that game, you can find the term in DnD as well. I would like to know what it means.

If you look for Cold Iron on Wikipedia, you only get iron: “Cold iron is a poetic and archaic term for iron.”
This would imply everything made mostly from Fe is cold iron. Clearly, this is not the case, in every game Cold Iron is something special, the every day sword is not made out of it.

The Dresden Files rulebook is not very specific about it:

something that anyone could reasonably get access to, but usually doesn’t carry on them (like cold iron) page 185.

What is cold iron?
How do I create cold iron?
How do I get cold iron?

To make the question easier to understand, compare Cold Iron to Holy Water. You know how it is different from usual Water, you know how you get it or create it.

Spirit guardians and iron golems

I have a room with two iron golems. They look like statues of a rider on horseback. They count as a single golem.

The party just finished a fight in last room. The cleric keeps spirit guardians active. They walk into the room with the iron golems. Do the golems take damage and animate and attack? Or do they stay hidden and look like a statue unless someone actually attacks them with a specified attack action? Normally the golems will not do anything unless attacked.

Also does truesight detect that the golem is in fact “alive”?

Does an Iron Defender mounted by an artificer still get its actions, if commanded?

Playing a human artificer battle smith with the spell Enlarge/Reduce, I want to use the Steel Defender as a mount. It is a medium size construct that becomes large size under the effects of the spell.

You may design the Steel Defender as you like, given that:

You determine the creatures appearance and whether it has two legs or four; your choice has no effect on its game statistics. (Eberron – Rising From the Last War, pg.61)

Even though it has “no effect on game statistics,” we can assume we care enough to design it in such a way it may act as a suitable mount.

The PHB rules for a mount in combat state, on pg.198:

…and it has only three action options: Dash, Disengage, and Dodge.

But also says, shortly after:

An independent mount retains its place in the initiative order. Bearing a rider puts no restrictions on the actions the mount can take, and it moves and acts as it wishes. (emphasis mine)

The Steel Defender has an intelligence of 4, meaning it does not automatically (and always) act as an independent mount (it is not sufficiently intelligent). Yet, according to this question and accepted/upvoted answer all mounts may act independently.

Yet in the rules-text for the Steel Defender (pg.61 of Eberron – Rising From the Last War) it says:

It can move and use its reaction on its own, but the only action it takes on its turn is the Dodge action, unless you take a bonus action on your turn to command it…

One more relevant rule:

…the Steel Defender shares your initiative count, but it takes its turn directly after yours.

Which is the same as the PHB rules for a mounted creature.

If I use my bonus action on my turn to command it while mounted, may it still use its Force-Empowered Rend or Repair action on its turn?

Related Questions

What are the benefits of having a mount?

How does a Gnome Battle Smith artificer (UA) riding his iron defender control it?

How do I determine if a creature is too intelligent to be a controlled mount?

Does a controlled mount share its rider’s turn?

Can a controlled mount make an Opportunity Attack?

Essentially what I’m going for (Image from Final Fantasy Brave Exvius):

Power Armour

Not that the rules care what it looks like. It could just as easily be a mechanical horse.

Is this Way of The Iron Fist homebrew monk subclass too overpowered?

This homebrew subclass is something I came up with to compensate for the fact that my group has only three members, and I as a monk am the only one remotely capable of tanking.

I call it the Way of the Iron Fist:

Way of the Iron Fist

You are a monk who has forged yourself into a weapon after years of brutal training and hardship to atone for a past evil and fight as a defender of the common people.

Iron Fists

At third level when you assume this tradition, your fists and feet become as hard as iron from years of brutal training in martial arts. This grants you the ability to deal 3 extra damage on unarmed strikes. Your fists also have the ability to strike the ki of the creature that you are striking, allowing you to siphon their ki and regain up to 3 HP per melee attack if you are striking an enemy while injured.

Iron Defense

At third level, due to the iron strength of your limbs, you are capable of blocking melee weapons with your hands. If a melee attack hits you, you can choose as a reaction to make a Dexterity saving throw against your ki save DC; if you succeed on the saving throw, you can, as a last ditch defense, catch the melee weapon with your hands to deflect the blow.

Iron Heart

At sixth level, you can have an extra strike added to Flurry of Blows.

Iron Will

Upon reaching 11th level, your will has become as strong as iron from brutal mental conditioning and transcending your fears to resist those who attempt to control your mind. You cannot be charmed, frightened, or put to sleep. You also gain resistance to psychic damage, and creatures cannot see your thoughts or intentions due to your strength of mind.

Iron Body

After years of self-imposed hardship to toughen your body, your entire body has become as strong as iron. You no longer feel pain and cannot be incapacitated by physical blows, and gain resistance to bludgeoning, slashing, and piercing damage.

I really love this subclass idea as it fits perfectly with my character’s backstory, but I am afraid it would make them way too overpowered and unbalance the game.

Is there any way maybe I should change it to make it less overpowered if it is too strong?

Can you combine the feats Iron Palm Technique and Dragon Style?

A party member of my campaign wants to get both Iron Palm Technique and Dragon Style.

However, it is unclear for us if it is possible to combine these two feats and what the result will be.

Iron Palm Technique makes it possible to use your constitution modifier instead of your Strength modifier for unarmed strikes. However, the Dragon Style will convert 1-1/2 times the strength modifier on the damage roll for your first unarmed strike on a given round.

Can they actually be used together, and how do they combine?

For a UA 2019 Battle Smith artificer, does the Iron Defender’s attack bonus increase with the artificer’s proficiency bonus?

Does the to-hit bonus of the Iron Defender’s Bite increase when the proficiency of a Battle Smith Artificer (from the 2019 artificer UA) increases?

The starting bonus is +4 (which I assume is the Iron Defender’s STR modifier + proficiency bonus), but nothing in the subclass’ description indicates that the bonus changes.

How many hit points does the Battle Smith Artificer’s iron defender have?

The iron defender’s stat block, under “hit points” says the following:

equal to five times your level in this class + your Intelligence modifier + the iron defender’s Constitution modifier

I could read this two ways:

Way 1:

equal to five times (your level in this class) + your Intelligence modifier + the iron defender’s Constitution modifier

Or way 2:

equal to five times (your level in this class + your Intelligence modifier + the iron defender’s Constitution modifier)

Which of these readings is correct?

iron fence

Our Factory
Our factory is a large morden enterprise which professional engaged in the designation, R&D,sales and installation of first-class balcony fence,stair railing,window fence and intelligent security system. We have more than 10 years experience in this field.
Our Product
Our products includes the following: American standard steel fence, aluminum fencing, balcony fence,and stair railing
Product Application
Fencing are widely used in the following industry:
Building materials industry, traffic facilities, landscape architecture
Our Certificate
We always feel that all success of our company is directly related to the quality of the products we offer. They meet the highest quality requirements as stipulated in ISO9001, SGS guidelines and our stringent quality control system.  We have four Utility Model Patent Certificates,We got the honor of China building materials industry top ten brand of green environmental protection.
Production Equipment
Large imported electrostatic spraying equipment
Production Market
We have customers from both domestic market and oversea market. Our main sales market: North America 60% Europe 20%,Australlia 10%, Southeast Asia 10%
Our ServiceBesides our existing molded products, we also can produce fencing products according to the drawings or samples from our customers. We control the product quality critically for every step during the manufacturing.Our products easily assemble,20 year warranty.iron fence

How does a Gnome Battle Smith artificer (UA) riding his iron defender control it?

I don’t see any reason a gnome Battle Smith artificer (from the May 2019 UA) couldn’t ride his iron defender RAW–it’s got the appropriate anatomy and is one size larger.

But how is it “Controlled”? Controlled has a specific meaning in mounted combat: A controlled mount acts on the riders turn and does not get attacks, an uncontrolled mount goes on it’s own initiative and gets attacks. An intelligent mount can only be uncontrolled, with an animal intelligence mount you get the choice.

I don’t believe the Iron defender has a free will though, it is always controlled by the Artificer that constructed it.

So if the Iron defender was being ridden, I’m guessing it could be in “Uncontrolled” mode, going after the Artificer, and still get it’s regular attack actions–but directed by the Artificer (Still essentially controlled).

On the other hand–you might want to be in “Controlled” mode if you didn’t need the Iron Defender’s attack–for instance if you were going to charge with a lance, have the artificer hit, then run away.

So my questions are–is my research (and assumptions) correct as I stated above, and if so, is there any way to switch between controlled and uncontrolled mode?

If you were riding an animal, I’m guessing the “Mode” might be determined by how you control it… or perhaps it cannot act on it’s own if it has a bit in it’s mouth and reigns? For the Iron Defender I can’t think of any differentiation that would apply except the Artificer’s will.