Design Guide


Creating your Colonist

Below you will find all current genes for all playable races on Xiunus. This goes from universal markings (such as underbelly and choker) to markings that are white and cover other markings (such as appaloosa and sabino) to markings that simply modify other genes' appearances (such as cream, artifice, and ticking). There are also species-specific markings (such as impala for tsabhua) that can be found under their specific species name below.

If you have questions about markings and designs, feel free to shoot Uri (preimpression) a message with your question and they will assist however they can.

Free Colour Ranges

Usually, markings should be from the same colour family as the base coat, but the following ranges are also allowed.

Free marking range for light markings. Free range for dark markings.

Left: Free range for Lighter markings (ie. Underbelly, Nyala.) or dark markings with reversal.
Right: Free range for Darker markings (ie. Points, Stripe.)

Eye Colours

Eye colours, except when explicitly stated for a species, can be any colour except for extreme black or extreme white. They can be unnatural colours without any need for an item or inherited colours. While tsabhua pupils are generally slits, belemoid pupils are more often than not round. They both can expand to be quite circular in reaction to light or emotions but there should always be some sort of iris colour visible.

Heterochromia, regardless of complete or segmental, is also freely available for any colonist, unless there is a restriction on the species.

Albino colonists should have eye colours from the following general colours: red, pink, or blue. Also, keep in mind that the skin colour can peek through fur at thin points such as nostrils and toes.

Free White/Black

Minimal white and minimal black are available for any colonist, unless they have another gene that supresses these markings. These use the colour ranges from Free Ranges above and must never be true white (#FFF) or true black (#000). These markings should be solid unless affected by the modifier ticking and must be at least somewhat hard-edged for the majority of the "marking."

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Claws, Horns, Skin

As of March 2020, colonist's claws and skin must always be darker than the fur they're touching. They also should be either similar to the base coat near them in saturation and coloration or natural in shade. Remember that fur colour is dictated by skin colour in most cases, so a hairless colonist with white spots will have areas of darker skin and areas of lighter skin.

Horns can be darker or lighter than the markings around them. They can be ivory, black, white, or similar natural colours. They can also be affected by markings on the body, even if they are near the tail or affected by artifice. If you have artifice, you may pick just the horn as your affected body part/marking if you would like!

Darker Value

Markings that have this rule must be darker than both the base coat and any markings they cover.

Lighter Value

Markings that have this rule must be lighter than both the base coat and any markings they cover.

Black Marking

Unless paired with another Value or affected by an appropriate Modifier, any markings should be either from this black range or appear black.

White Values

Unless paired with another Value or affected by an appropriate Modifier, any markings should be either from this white range or appear very pale.

Warm Colours

Very few markings have this rule. This marking can have warm colours from this range.


This marking has the ability to have the REVERSAL Modifier Marking applied. View the Reversal modifier page for more information.
Note that in order for the reversal modifier to be in effect, the marking must be in its dominant form (X X vs X x) and both pairs must have the (+r) reversal allele modifier hooked on.


These markings must be solid. They cannot have holes in them unless affected by a modifier that causes holes, such as Ticking.

They also should generally be connected, except for in the cases where they are very distant from one another.

Large Holes

This marking should have large holes across its range. Hole edges should never be very blurred in entirity - there should be soft or hard edges to parts of them to make it clear that they aren't just a missed area on markings.

Small Holes

This marking should have small holes across the range.

Hole edges should never be very blurred in entirity - there should be hard edges to parts of them to make it clear that they aren't just a missed area on markings.

One Toned

These markings may only have one tone, value, or hue across. All markings may have very slight tone shifts across the form, but they should for all purposes appear to be one color.

Two Toned

These markings can have two tones, though be aware that some require Dominance or some other condition to allow two tones.

The two tones must simply be adjustments of the same color, although when modified by Artifice, you may pick either one or both tones to be affected.


This marking should be so blurred as to appear a gradual gradient across the edges of the marking.

Hard Edges

These markings should be hard-edged, and fur texture is often encouraged.

Slight "blurring" (a blurred edge behind the sharp edge) is allowed in most cases.

Soft Edges

These markings should be soft edged but should still be clearly formed. They should not be so faded as to appear to be Gradient, unless paired with that rule.

Blurred Edges

Generally a hard or soft edged marking that can have areas that are blurred into the base coat or other markings. This should not be the entire marking!


This marking can have Mapping or Haloes around its edges, where the marking seems to bleed out in a lower opacity version of itself.

Except for in the case of Heartfire, maps should always be fairly consistent with their marking - they should not expand too far.


This marking can be faintly visible through White Spotting markings.


Markings with this Rule applied can have variations in the opacity across the marking. In cases where this requires an additional gene or requirement, such as with the Peacock variant of Leopard Appaloosa, this Rule will not be applied to the marking to make it clearer when markings can be freely Faded.

Genetics Overview

Genetics in Xiunus is loosely based off of real world genetics, with dominant and recessive heredity as well as heterozygous possibilities.

Regular genes are those where a gene will be visible if the gene is homozygous dominant (Gn Gn) or heterozygous (Gn gn,) whereas recessive genes are those where the gene will be visible if the gene is homozygous recessive (gn gn). If the gene does not have "recessive" mentioned at all in its description or button, it is likely a regular gene that follows normal rules.

A phenotype is the written-out explanation of a genome, whereas the genome or genotype is the list of allele pairs used for breeding purposes. Note that in the phenotype, if a gene is within parentheses (like this), it means it is carried, not shown - these colonists can't have the markings visible but they may pass them on to their offspring!

For the sex chromosome, we use Earth Mammalian terms. XX is female and XY is male.

The colour complex is more complicated - this consists of four pairs of alleles that match up to determine the base coat colour. There are several other genes that affect the base coat, such as the cream complex or other modifiers such as greying or countershading, but these four are the most important. Each species has a different set of base coat ranges and names, so it's important to look at the ranges for the species you are focusing on.

The greying gene and dun both follow regular dominance, as mentioned above. A colonist with "G G" will have greying and will always pass it, while a colonist with "D d" has a 50% chance of passing on the dominant "D" allele.

The flaxen and countershading genes are both recessive - in order to display one of the two genes, it must be recessive dominant (cs cs or f f). For markings like these, if they are heterozygous it means the colonist carries the gene and it will be displayed in parentheses at the end of the phenotype.