Steel Defender DnD 5e — Meet the Artificer’s Robot Dog

Last Updated on January 22, 2023

What Is a Steel Defender?

A steel defender is a construct companion that aids the battle smith artificer. Technically speaking, “steel defender” refers both to the stat block for this creature and to the subclass feature that allows an artificer to control the creature. 

The steel defender is very similar to a summoned creature or a familiar in that it is a creature under the control of a PC. This is great because it improves a player’s impact on the overall action economy, but there are definitely more benefits than that to be had.

Before we get into the actual stats of this creature, let’s nail down what exactly it is. 

A steel defender is a medium construct with a predetermined stat block. However, its appearance is completely up to the artificer themselves. You get to decide whether this thing is on two legs or four and any other aspects that you fancy. The downside, or rather, the balanced side, to this is that the appearance has no effect on the actual game statistics of the creature.

This means that wings don’t give the steel defender flight, being modeled after a crocodile doesn’t let this construct bite, and you’re stuck with the stats as written. 

While that might be a bummer for those looking to fly around on their robot pegasus, it’s not the end of the world. The actual stats for this creature are pretty good, and they’re certainly worth keeping. But enough messing around, let’s actually look at these stats and see how they stack up.

Steel Defender Stats

Medium construct

  • Armor Class: 15 (natural armor)
  • Hit Points: 2 +  your Intelligence modifier + 5 times your artificer level (the defender has a number of Hit Dice [d8s] equal to your artificer level)
  • Speed: 40 ft.
  • STR 14(+2), DEX 12(+1), CON 14(+2), INT 4(-3), WIS 10(+0), CHA 6(-2)
  • Saving Throws: Dex +1 plus PB, Con +2 plus PB
  • Skills: Athletics +2 plus PB, Perception +0 plus PB x 2
  • Damage Immunities: Poison
  • Condition Immunities: Charmed, exhaustion, poisoned
  • Senses: Darkvision 60 ft., Passive Perception 10 + (PB x 2)
  • Languages: Understands the language you speak
  • Proficiency Bonus (PB): Equals your bonus

Vigilant. The defender can’t be surprised


Force-Empowered Rend. Melee Weapon Attack: your spell attack modifier to hit, reach 5 ft., one target you can see. Hit: 1d8 + PB force damage.

Repair (3/day). The magical mechanisms inside the defender restore 2d8 + PB hit points to itself or to one construct or object within 5 feet of it.


Deflect Attack. The defender imposes disadvantage on the attack roll of one creature it can see that is within 5 feet of it, provided the attack roll is against a creature other than the defender. 

As a basic stat block, perhaps the most impressive thing here is the amount of features and abilities tied directly to your advancement as an artificer. Like any creature, it uses its proficiency bonus on any attacks or ability checks where it is proficient. Fortunately, its PB isn’t just static though. It gets the same PB as you do, and you’ll be leveling up.

This is huge because it’s so different from the other options we have had for familiar-type creatures. Normally, a familiar or summoned ally is going to have the same effectiveness at level 20 as it did at level 1. The steel defender is always growing, though, because you’re always growing.

There are even a couple of features you’ll receive as you level up that directly benefit and improve the defender beyond this base. 

The first is Arcane Jolt at 9th level, which lets you channel magical energy whenever you or your steel defender hit a target with an attack. When that happens, you can either dish out an extra 2d6 force damage or you can choose a creature within 30 feet of the target to heal by the same amount (2d6).

At 15th level, the capstone ability of this subclass, we see a few more benefits. The arcane jolt increases to 4d6, and our steel defender gets a +2 bonus to AC. Additionally, whenever our defender uses Deflect Attack, the attacker takes force damage equal to 1d4 + your Intelligence modifier.

All of these abilities meld well to create a pretty badass robot ally at your command. Most notable is the fact that your defender can impose disadvantage on an enemy’s attack rolls every single turn if it’s placed correctly on the battlefield. 

Its basic abilities and immunities aren’t too shabby either. Expertise in perception means your defender can serve as a watchful guardian at night, and since it doesn’t suffer from exhaustion, it never needs to sleep or eat. 

Immunity to charm and poison are pretty par for the course when it comes to constructs, but it means you have an effective creature that can avoid some of the worst, and most common, conditions out there.

Its attack is also nothing to shake a stick at. On its own, 1d8 isn’t that much, but remember that this is basically just an extra attack for you, and you can’t find a single player that would turn down the ability to deal 1d8 extra damage every turn.

How Does the Steel Defender Work?

The steel defender isn’t a completely automated piece of machinery. While the creature shares your initiative, it isn’t a direct extension of yourself. It still requires you to command it to take most actions, but it does at least maintain the ability to do some things of its own volition.

Left alone, the steel defender will move, Dodge, and use its Deflect Attack reaction when possible. That means, without you having to do anything at all, your steel defender will put itself exactly where it needs to be and then impose disadvantage on attacks against itself and a member of your party.

Of course, you can command it to do more or to move to a specific location. On your turn, you must use a bonus action to issue a command. The command can dictate all of its actions for the next round, or it can be as simple as attacking a certain creature, leaving its movement and reaction up to itself.

As a battle smith, you likely won’t have too many spells or attacks reliant on a bonus action, so you should be able to easily command your defender on each turn. It’s not the end of the world if you can’t though since it will do the most logical thing in any situation.

As far as using the defender effectively, it makes the most sense to use it for the safety of you and your allies. It is, after all, a defender. 

In combat, you should only really have it attack if the attack is going to make a large difference. More often than not, it’s best to just not paint a target on its back and allow it to feel like a passive ability that is protecting your allies.

Outside of combat, you can get a lot more creative with how you use it. This is when its appearance might actually have an effect. You may want a gorilla-themed steel defender so it can use opposable thumbs and grab onto things. Or you may try convincing your DM that you can ride it outside of combat. 

Essentially, combat is well defined, but everything else is up to interpretation and solid reasoning. The artificer class is designed to create new and exciting magical items, so it stands to reason that you can modify your defender in much the same way.

Modifying Steel Defenders

A while ago, this might’ve been known as magical research. Today, it’s whatever you want to call it, but it’s a sometimes neglected feature of the game. Classes with access to magic can and should be able to use their downtime devising new and exciting ways to harness their potential.

For an artificer, this can mean building a fresh new contraption, repairing magic items, practicing enchantments, or, most importantly, modifying your steel defender. 

Before I get into the exciting possibilities, I need to tell you the requirements. The first thing you need is your DM’s approval. If your DM won’t let you craft a new skin of improved natural armor for your defender, then you won’t be doing it. 

With that out of the way, the other two pieces of the puzzle are time and supplies. A wise artificer should collect any trinkets of magical potential, be they organs of a strange beast, fragments of artifacts, or miscellaneous runes. Whatever it is, you should be collecting things and stuff so you can tinker with them in your downtime.

Depending on the idea you propose, your DM may direct you to collect specific items and then set up those adventures accordingly. Perhaps a fragment of a beholder’s brain is necessary to create a telepathic link between you and your defender.

Time is a bit easier to come across, but much like crafting potions or armor, time takes time. 

With all that out of the way, I want to introduce a few options that may or may not fly at your table along with the requirements to build them.

1. New Creature Feature

A new feature for the defender based on the creature its appearance is inherited from. This could be an attack, an ability, a proficiency, or a reaction. Movement, AC, and HP cannot be modified in this way. 


  • A number of days (D) studying the creature in its natural habitat equal to 2 x its CR.
  • Two D spent creating and applying the upgrade. No spells can be cast during this time as the process requires a continuous flow of magic.
  • Appropriate supplies, typically copper, iron, and gold. Supplies must be worth 200 x the creature’s CR. To replicate the feature of a creature with CR greater than your level, you must slay the creature and perform an additional 1D of time studying the feature you intend to replicate.
  • Maximum applied features are equal to your intelligence modifier.

2. Increased Movement

The defender gains 5 feet of any variety of movement speed.


  • Five days studying a creature with the desired type of movement speed. No study is necessary to increase walking speed.
  • A number of days creating and applying the upgrade equal to the number of movement modifiers you have created so far + 2.
  • Essence of an appropriate elemental with CR greater than or equal to your proficiency bonus.
    • Flying: Air 
    • Hovering: Fire
    • Burrowing, Climbing: Earth
    • Swimming: Water
  • Additional supplies determined by your DM. Value must be equal to 100 + 100 x the number of movement modifiers you have created so far. 
  • Magical fuel. Once the modifier is applied, you must expend a spell slot to give it access to a modifier for one hour per level of spell slot. A spell slot can only activate one variety of movement modifier at a time (i.e., spend a 3rd level spell slot for three hours of access to fly speed.)

3. Increases AC

The defender gains a +1 bonus to AC. The defender’s AC cannot be increased past 20 in this way until you reach 15th level in this class at which point it can be increased to 24.


  • Metal materials valuing 100 x the current AC of the defender. 
  • A number of days equal to half the current AC of the defender rounded down.
  • Proficiency in Smith’s Tools.

These are meant to be a template. You can definitely use them as is, but this should definitely be a conversation with your DM while you’re not at the table actively playing a game. Hopefully, they will allow you to make some variety of modifications with the appropriate supplies and downtime, but be respectful if they say no; they likely have balance-related reasons to do so.

I hope you enjoy this awesome ally and that you get to use it to the fullest of its potential. As always, happy adventuring.

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