I recently created this homebrew race centered around the Modrons. To be honest, I am not overly familiar with their lore or that of Mechanus. Most of what I came up with here came from information from the wiki. The main "inspiration" that started this for me was the fact that some modrons look like dice, and I thought it would be funny if whenever one falls if it was like the universe was rolling a giant dice (which is reflected in the Fall of Order feature). Beyond that, I tried to come up with interesting features based around their lore, but let me know what you think. 

Isolated Modron

Isolated Modrons represent those who have been separated from Mechanus for an extended period of time, resulting in a loss of their immortality and some of the other blessings of Primus and their native plane. Some isolated modrons turn to a life of adventure in order to find a way to return to Mechanus. Others have found new meaning in their separation and seek to instill order on the material plane. 

Isolated Modron Traits

Ability Score Increase

Increase one of your ability scores by 2 and another by 1. 

Age

While on Mechanus, modrons are effectively immortal beings, so judging one’s true age is a difficult task as many will simply choose not to keep track of it. Most isolated modrons will instead judge their “age” on the material plane by the amount of time since they became separated from Mechanus. An isolated modron will generally not live for more than 101 years of long term separation from its native plane. 

Alignment

Modrons in their creation are beings of order and will tend towards a Lawful alignment; however, it is possible that one who has been on the material plane for an extended period of time may find its motives and mindset changed. 

Size

Modrons vary depending on shape, but will generally stand around 5 to 6 feet tall. Your size is Medium. 

Speed

Your base walking speed is 30 feet

Creature Type

Modrons are a mix of biological and mechanical parts. Most modrons can live off of energy alone, but time spent on the material plane has caused a reliance on food, water, and rest to sustain the biological parts of isolated modrons. 

Although modrons of Mechanus are constructs by design, due to your increased reliance on sustaining your biological parts you are treated as a humanoid. 

Law of Averages

An isolated modron’s connection to Mechanus, although weakened, allows them to impose order on the world around them in limited amounts. When you deal damage with a weapon attack or cantrip you can choose to replace the damage rolled with the average damage value instead. 

You can also use this feature to replace the damage rolled for a spell of 1st level or higher you cast with the average damage, requiring a number of uses of this feature equal to 1 + the level of spell slot expended. For example, if you wanted to use this feature after casting Burning Hands at 1st level, you would need to expend 2 uses of this feature. 

You can use this feature a number of times equal to your proficiency bonus, regaining all uses following a long rest. 

Consume Energy

Choose one of the following damage types: acid, cold, or fire. You gain resistance to the chosen damage type. 

Also, when you take damage of any of the types listed above you can use your reaction to reduce the damage you would take by 1d10 + your level. Using this reaction consumes the energy reduced, granting you enough nourishment to last 24 hours. Once you use this reaction, you cannot do so again until you complete a long rest. 

Languages

You can speak, read, and write Common plus one other language of your choice. You can also speak Modron, a language which sounds like a collection of mechanical clicking and whirring noises to those who cannot speak it. 

Subraces

When you choose to play as an Isolated Modron, select one of the following subraces which reflects your particular geometry 

Tridrone

Tridrones are shaped like inverted tetrahedrons, featuring an eye and mouth on each of its triangular faces. You gain the following traits

Triangular Perception

You gain proficiency in the Perception skill. You also gain a bonus to your Passive Perception score equal to half your proficiency bonus (rounded down).

Multitasker

You have an additional arm which can be used as a bonus action on each of your turns to take the Use and Object action provided the object is not magical.  

Fall of Order

Whenever you fall or are knocked prone, falling on one of your sides temporarily restores your connection to Mechanus and imposes some reordering of the plane you are one (although not always to your benefit). Roll 1d4 and consult the Fall of Order Table for the effect which transpires. This effect persists until you are no longer prone. After the effect occurs, you do not roll on the Fall of Order table again until after completing a short or long rest.  

 

Quadrone

Quadrones are shaped like simple cubes, featuring two eyes and a mouth on one of its faces. You gain the following traits:

Rudimentary Wings

You possess a set of wings, but your separation has set them into a dormant state where you can only use them for short periods of time every day. As an action, you can ready your wings and gain a fly speed equal to your walking speed. This feature lasts for up to 1 minute and you must maintain concentration on using your wings as if concentrating on a spell. If this feature ends while you are flying, you fall if you are still aloft.  Once you have used this feature you cannot do so again until you complete a long rest.  

Aerial Combatant 

You gain proficiency in longbows and shortbows. Using mechanical parts of your body, you can produce pieces of ammunition as an action. The number of pieces produced is equal to half your proficiency bonus (rounded down). Once you have created ammunition this way, you cannot do so again until you complete a long rest. 

Fall of Order

Whenever you fall or are knocked prone, falling on one of your sides temporarily restores your connection to Mechanus and imposes some reordering of the plane you are one(although not always to your benefit). Roll 1d6 and consult the Fall of Order Table for the effect which transpires. This effect persists until you are no longer prone. After the effect occurs, you do not roll on the Fall of Order table again until after completing a short or long rest.  

 

Fall of Order Table 

Rolled Value	Effect
1	Nothing happens
2	Attacks, ability checks, and saving throws made within 10 feet of you cannot incur advantage until the end of your next turn.
3	Attacks, ability checks, and saving throws made within 10 feet of you cannot incur disadvantage until the end of your next turn.
4	You regain an expended use of your Law of Averages or Consume Energy feature (your choice).
5	Spell effects of 1st level or lower within 10 feet of you are dispelled. Magic items and spells up to 3rd level are suppressed as if affected by the Antimagic Field spell until the end of your next turn.
6	Once during the next minute, when a creature you can see within 10 feet of you takes damage you can use your reaction to treat the damage die as all having rolled “1s” instead of their rolled value for the damage dealt to that creature.