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Invader: Little Green (Wo)men from Outer-space – (mostly) 5e Compliant, 1-20

My daughter’s Amazon died at the hands of a Rat-Leopard at level 1.  As she is in the maze I gave her the option to be a class/race that isn’t normally available in my world or campaign setting – as the Maze has a lot of strange creatures in it.  Her requirements amounted to “I want to be an Invader Zim”.  Here you go.

1-20 version.  I cap hit points so that’s something that prevents 100% 5e compliance, but that’s easy for a DM to fix.


The irken people are an imperialistic spacefaring race.  They are technological geniuses but lean more towards weird science than practical war machines – which is the only thing protecting the universe from being completely conquered by the Irken Empire. This is both a race and a class.

Class Features

As an Invader, you gain the following class features.

Level  XP  Proficiency Bonus Feature Title Hit Points Weird Science “Science” Stuff
1  0 +2 The Tallest Protects Me!, Big Brain, SIR Unit Junior Invader 4 + CON 1d6 1 in 6
2  300     Apprentice Invader 2d4 + CON 2d6 1 in 6
3  900     Invader 5th Class 3d4 + CON 3d6 2 in 6
4 2,700   Ability Score Improvement Invader 4th Class 4d4 + CON 4d6 2 in 6
5 6,500     Invader 3rd Class 5d4 + CON 5d6 2 in 6
6  14,000     Invader 2nd Class 6d4 + CON 6d6 3 in 6
7   23,000     Invader 1st Class 7d4 + CON 7d6 3 in 6
8   34,000   Ability Score Improvement Invader Lieutenant 8d4 + CON 8d6 4 in 6
9   48,000     Mad Scientist 9d4 + CON 9d6 4 in 6
10   64,000   Perfected Technology  Invader 10d4 + CON 10d6 5 in 6
11 85,000  –  – 11d6 5 in 6
12 100,000 Ability Score Improvement  –  – 11d6 5 in 6
13 120,000  –  – 11d6 5 in 6
14 140,000  –  – 11d6 5 in 6
15 165,000  –  – 11d6 5 in 6
16 195,000 Ability Score Improvement  –  – 11d6 5 in 6
17 225,000  –  – 11d6 5 in 6
18 265,000 Tech Mastery  –  – 11d6 5 in 6
19 305,000 Ability Score Improvement  –  – 11d6 5 in 6
20 355,000 Signature Technology  –  – 12d6 Advantage 5 in 6

Ability Scores

You get +2 Intelligence and -2 Wisdom.  Your Wisdom can never be higher than 10 but your Intelligence can be improved to 30.


You mature at the same rate humans do, and most are expected to settle down into an adult life by around age 20. They otherwise have normal human life expectancy.


You are most often chaotic.


You are between 3 and 4 feet tall and an average of about 40 pounds. Your size is Small.


Your base walking speed is 25 feet.

The Tallest Protects Me!

When you roll a 1 on the d20 for an attack roll, ability check, or saving throw, you can reroll the die and must use the new roll.


You can speak, read, and write Common and as many languages as your Intelligence bonus allows. You may choose these languages during character creation or during play but once chosen they are locked.

Hit Points

Hit Dice: 1d4 per invader level but maximum hit points at level 1.
Hit Points at Higher Levels: 1d4 (or 3)


Armor: Light (including any technologically-based shields that do not require a hand to use – for example, an energy shield).
Weapons: Big Guns, Small Guns, Energy Weapons, Daggers

Tools: All simple technological-based tools.
Saving Throws: Intelligence x2
Skills: Arcana and any other skill from History, Insight, Investigation, and Medicine


You start with the following equipment, in addition to the equipment granted by your background:

  • (a) a lazgun or (b) an energy dagger (as a dagger but does force damage)
  • (a) a bag of bitz that you use to create your gadgets.
  • (a) a scholar’s pack or (b) an explorer’s pack
  • A book of schematics (this is where all your gadget plans are stored).

Ability Score Improvement

When you reach 4th level, and again at 8th level, you can increase one ability score of your choice by 2, or you can increase two ability scores of your choice by 1. As normal, you can’t increase an ability score above 20 using this feature with the exception of Intelligence.  If this improvement is used on Intelligence you may increase your intelligence by 3 but reduce your wisdom by 1.

With DM consent, you can forgo taking this feature to take a feat of your choice instead.

Big Brain

On any technological item that allows you to add an ability score modifier you may use your INT bonus instead. On items not sufficiently “weird science-y” enough you take a penalty in the items use equal to your INT (includes anything available on Earth during the 21stCentury or older is considered “archaic” and not “science-y enough”. You may always add your INT bonus when using your weird science class ability.

For example, when using a lazgun you can add your INT modifier to to-hit and damage rolls instead of DEX.  When using a longbow you subtract your INT modifier from your to-hit and damage rolls.

“Science” Stuff

You know “science” stuff and are good at planning ahead and having the right, albeit overly complicated tool, ready.  You may use “science” stuff for the following as a bonus action:

  • Whenever you encounter unknown technological artifacts (“magic” items in the world of Pangaea) you can identify its use by rolling this die.  On a success you identify how to use it, however, you come up with a completely weird science theory as to its working or original use which is totally off the mark but impressive sounding.
  • You may also use this skill to have any minor technological gadget or material you need on hand in your bitz bag.
  • You can roll to try and get your SIR unit to focus and follow orders for 1 round,
  • You may use this ability to also decipher arcane scrolls and use them since arcane magic is just advanced calculus – elementary for a superior irkan invader! However, failure means the spell backfires (Left to the DM’s imagination).
  • As well as for more general utility-related actions – things that would not consume a die from your weird science trait with the approximate utility of a cantrip.

SIR Unit

You start the game with a Standard Issue Recon Unit or SIR for short.  This is a robot companion. This companion can take any form you like but must be Small or Tiny size.  Pick any creature of Small or Tiny size as your companion (with DM’s approval, CR 1/2 or less) and by default, the SIR unit takes this form and has this creatures starting statistics. The SIR unit adds your INT modifier to its AC, Saving Throws, to-hit, and damage rolls, as well as to any saving throws and skills it is proficient in. Its hit point maximum equals the hit point number in its stat block or four times your invader level, whichever is higher. However, due to the imprecise nature of irken technology the SIR unit acts randomly each round per the table below:

d10 SIR Unit Behavior 
1  The SIR Unit runs off in a random direction this round.  It may return with an item you requested it to retrieve in the previous month or do some other random activity – like bake you some muffins.
2-6  The SIR Unit doesn’t do anything this turn.  It rolls around crying on the floor about “piggy” or some other nonsensical activity.
7-8  The SIR Unit randomly attacks a target determined randomly – but it will never attack it’s Invader.
9  The SIR Unit acts normally – it’s kind of suspicious it’s listening to you all of a sudden.
10  Warmachine mode. The SIR Unit has a moment of lucidity and reverts to its original design as a warmachine. It does whatever you tell it to without fail and with advantage on any roll required to perform the activity. If it is in combat it may use all its attack options as if it has Multiattack (if it already has multiattack, it uses that plus its other options) and automatically scores a critical hit on all attacks that hit.

If a SIR Unit is destroyed in battle you may rebuild it after a long rest. All SIR Unit’s have the following Reaction:

Interceptor (1/Day). If the invader the SIR Unit serves is reduced to 0 hit points by an attack and the invader is within movement range the SIR Unit moves up to its speed and absorbs the killing blow (which may destroy the SIR Unit).

You may spend ∆ρ 500 (drachma/gp) and a long rest to upgrade your SIR Unit with the following traits:

  • Force Fields. You add a flickering force field to your SIR Unit sheathing it in a thin layer of shimmering energy that grants a number of bonus hit points equal to 4x your level. All damage dealt to a robot with an active force field is reduced from these hit points first. As long as the force field is active, the robot is immune to critical hits. A force field regenerates at the start of your round a number of hit points equal to your level, but once the force field’s hit points are reduced to 0, the force field shuts down and does not reactivate until you complete a long rest.   If you have also added the Explosive Clap upgrade, that ability triggers when the shield is exhausted.
  • Tank. You bolt on some rusty plates improving the SIR Unit’s armor class by +2.  You may select this upgrade multiple times for a cumulative benefit.
  • Explosive Clap. The SIR Unit creates an explosion that damages all nearby creatures.   An explosion centred on the SIR Unit with an area-of-effect of a 20-foot sphere that does 3d6 force damage. You and the SIR Unit are immune to this attack.  You may select this upgrade multiple times for a cumulative benefit of one extra die of damage.
  • Death Ray! You add an integrated long-lazgun to the SIR Unit.  On a natural 1, the long-lazgun does not permanently deplete like normal technological items but stops working until you take a long rest.
  • Make it Sparkle! You imbue your SIR Unit’s melee attacks with a particular element.  Add an additional 1d6 elemental damage of any type you wish to the SIR Unit’s melee attack.  You may add further elemental types by picking this upgrade multiple times.  If the SIR Unit has more access to more than one element the type of elemental effect can be determined by you from round-to-round as a free action.  However, assuming you roll a 9 or 10 on the SIR Unit’s behaviour table, the SIR Unit is intelligent enough to select the appropriate type under most circumstances.
  • Glory of the Irkan Empire! This upgrade allows the SIR Unit an extra attack per round.  It may not be selected more than once.
  • ROCKET BOOTS! The SIR Unit now has a fly speed equal to its speed.
  • Unobtainium Weaponry. The SIR Units attack are considered magical.

The cost of each new upgrade includes the previously spent amount +500 ∆ρ.  For example, the first upgrade is ∆ρ 500, the second 1,000 the third 1,500, etc.

Weird Science

You have a number of d6 you can use per day to create a technological effect of your choosing. This is a one-time effect (at the DM’s discretion). The sum of these dice determines the to-hit roll and damage and/or the required skill check. However, once your die is used it used until you take a short or long rest.  A long rest resets all die, a short rest returns 1d6 dice to your weird science pool (up to your normal maximum). If you ever roll doubles on any of these checks the technology malfunctions in a spectacular way.  This doesn’t mean what you were attempting to do fails, it just means something strange – and potentially deadly – happens.

For example, you come to a locked door and decide to use 3d6 and your universal-screwdriver to open the door.  The DC to pick the lock is 10 and you roll 11 with 3d6.  You successfully open the door without issue but you now have lost the use of 3d6 until you take a long rest (or short rest and roll to recover them).  If you rolled an 11 with a double (say 5, 5, and 1) your universal-screwdriver opens the door by triggering a micro-blackhole which destroys the door and triggers such a loud bang that you automatically have a random encounter.

You do not expend your die if you fail to meet the target number.

As a guide, the power of “science” stuff should be about the same as a spell of the same level. These are one-use items.

Perfected Technology

At 10th level, you may permanently sacrifice a weird science die to build a permanent, non-flawed technological item or upgrade an item you already possess. If the item would normally have a material cost to create this is satisfied by the sacrifice of your weird science die.  What exactly can and can’t be built is at the DM’s discretion but the DM should be generous in what can and can’t be built for 1 die as it is a permanent sacrifice of a class ability.

Tech Mastery

At 18th level, you have achieved such mastery over certain technologies that you can use them at will. To represent this, choose a 1st-level wizard spell and a 2nd-level wizard spell. You can cast those spells 1/day without consuming any weird science dice.  You can expend a weird science die to cast it again that day.

Signature Tech

When you reach 20th level, you gain mastery over two powerful technologies and can use them with little effort. To represent this, choose two 3rd-level wizard spells as your signature tech. You always have these spells prepared, they don’t count against the number of spells you have prepared, and you can cast each of them once at 3rd level without expending a spell slot. When you do so, you can’t do so again until you finish a short or long rest.

If you want to cast either spell at a higher level, you must expend a weird science die per spell level above 3rd.


Invaders may spend gold and 1 week to build the following “golem armor” (technology-based armors).

Armor Name  Cost  AC Notes
Jump Suit                5 11 + Dex modifier
Scatterlight              45 12 + Dex modifier Resistance to radiant damage
Synth breastplate              50 13 + Dex modifier (max 2) Advantage with heavy weapons
Innsuit            100 14 + Dex modifier (max 2) Resist 1 energy type of your choice when purchased/built
Smart Armor (compact)            750 15 + Dex modifier (max 2) Minimum Arcana, +4, DR 1
Smart Armor (full)              30 14 + Dex modifier (max 2) Minimum Arcana, +6, DR 2
Metalweave Armor              75 16 + Dex modifier (max 1) Minimum Arcana +8
Nanite Ablative Armor            200 17 + Dex modifier (max 1) Minimum Arcana +9, Resistance to nanite attacks
Exoskeleton Armor         1,500 18 + Dex modifier (max 1) Minimum Arcana +10, +2 STR, DEX, Resist Bludgeoning, Piercing and Slashing as well as Radiant damage.
A character that has “sciencey” stuff or a similar skill may build tech-armor using their sciencey stuff skill.  It costs half as much and takes 1 day of downtime. On a fail, you still build the armor but it has a fatal flaw (DM’s discretion).

Example SIR Unit:

SIR UNIT 892374 “Iggy”

Small construct, same alignment as owner
Armor Class 12
Hit Points 7 (1d6 + 1)
Speed 40 ft.
13 (+1) 14 (+2) 12 (+1) 8 (-2) 12 (+1) 7 (-2)
Skills Perception +3
Senses Passive Perception 13
Languages Common

Keen Hearing and Smell. The SIR Unit has advantage on Wisdom (Perception) checks that rely on hearing or smell.


Iron Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage. If the target is a creature, it must succeed on a DC 11 Strength saving throw or be knocked prone.


Interceptor (1/Day). If the invader the SIR Unit serves is reduced to 0 hit points by an attack and the invader is within movement range the SIR Unit moves up to its speed and absorbs the killing blow (which may destroy the SIR Unit).

Posted in 5e, Adventurer's Vault, Clash of the Titans, Class, Dungeons & Dragons, Maze of the Blue Medusa


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