Rachni

A Rachni Queen

The **rachni** are an insect-like species from the planet Suen, thought to be extinct. They threatened Citadel Space roughly two thousand years ago during the Rachni Wars. Intelligent and highly aggressive, the spacefaring rachni were driven to expand and defend their territory. They were eventually defeated and completely eradicated by the krogan, who had been uplifted by the salarians for their combat prowess and physical resilience to directly confront the rachni in the harsh environments of their worlds. The accidental discovery of the rachni led to the Citadel races curbing their rapid expansion, in fear of being plunged into another galactic war.

## History

### Ancient History

The rachni, a species of spacefaring insects guided by a hive-mind intelligence, evolved on Suen, a planet tidally-locked to its red dwarf star. Life developed in a habitable terminator zone between hemispheres that were constantly scorched or perpetually frozen. The harsh conditions of Suen's surface forced the rachni to forage underground amid sprawling subterranean river systems.

Sometime at the height of the Prothean Empire, the Protheans discovered the rachni and bred them as weapons of war, selecting for the most cunning and warlike queens and unleashing rachni swarms on their enemies. Eventually, the rachni became too difficult to control and turned on their Prothean masters. The Protheans attempted to eradicate the rachni and destroyed as many as 200 worlds before they were satisfied the rachni were extinct, but enough survived on Suen to replenish their population.

### Advent of Civilization

As the rachni developed civilization, they established surface cities on Suen. Wrestling with the engineering problems of Suen's extreme surface environment may have given the rachni their first insights into how to build interstellar spacecraft. After achieving spaceflight, the rachni first traveled to the neighboring planet of Kashshaptu and discovered a crater there known as "the howling gulf", which featured an abundance of element zero. The rachni obtained samples of the eezo and studiously researched its properties, but would not develop FTL technology until centuries later.

### The Rachni Wars

Around 1 CE, salarian explorers opened a mass relay to a previously-unknown system and encountered the rachni, who promptly captured them. The rachni used their extensive research on element zero to reverse-engineer the FTL drives of the explorers' starships. They proceeded to construct FTL vessels of their own and rapidly expanded into the galaxy, ushering in the Rachni Wars.

Attempts by the Citadel races to negotiate were futile, as it was impossible to make contact with the hive queens that guided the race from beneath the inhospitable surface of their homeworld. It was assumed that the rachni were irredeemably hostile and could only be stopped through warfare, but the rachni had the upper hand and overwhelmed defenses with their sheer numbers.

The emergence of the krogan in 80 CE turned the war against the rachni. Able to survive the harshest environments, the krogan were able to strike at the queens in their lairs and reclaim conquered Council worlds. When krogan fleets pushed them back to Suen, the rachni refused to surrender. The krogan response was swift and brutal: they bombarded Suen's cities and detonated powerful bombs in the rachni's underground nests, creating massive sinkholes on the planet's surface. The rachni were declared extinct in 300 CE, although in caution the Citadel Council left a listening post in the system to monitor for any survivors.

## Biology

### Subtypes

* **Rachni Worker** - Workers are the smallest type of rachni. They appear as small green enemies and their main attack is a suicide explosion that releases toxic damage over a wide radius.
* **Rachni Soldier** - Soldiers are slower, but much larger creatures than Rachni Workers, with thin tentacles ending in little pods. Soldiers are the main defenders of rachni held areas and can cause toxic damage with their spit.
* **Rachni Brood Warrior** - Brood Warriors are rachni who are much larger and stronger than normal Rachni Soldiers. They are the only male-gendered rachni and they have some biotic ability.
* **Rachni Queen** - Queens are the largest and most intelligent of the rachni. Queens lead the rachni and provide guidance for the rest of their species.

## Culture

The rachni are a territorial race, determined to remain isolated from the rest of the galaxy. They normally inhabit extremely hazardous worlds, able to survive environments that would kill most sentient species. Should their territory be invaded on purpose or even by accident, they respond with swift and brutal force.

However, many make the mistake of underestimating the rachni as mindless animals when in fact the rachni are an extremely intelligent sentient species. The rachni achieved space flight and a form of cryogenic suspension, developed weapons and carved out a huge swathe of galactic territory. Far from being treated as disposable resources of the hive, rachni soldiers are carefully nurtured as part of the group.

The queens are the leaders of the rachni hive mind. Their ways of perception, thinking and communications seem to be different from that of other races, and based upon a synesthetic perception of sound as both sound and color. Rachni communication is geared towards pheromones, and, as further proof of their intelligence, an organic quantum entanglement communicator - not, as so many believed, telepathy.

Rachni regard speech and thought as forms of music, as shown by the strange metaphors used when attempting to communicate, for example, "songs the color of oily shadow". The speech patterns used by them in such occasions are also unusual; "When we speak, one moves all". They refer to their manner of communication as "singing", which soothes and nurtures their young, and this appears to colour their entire psychology - for example, the rachni speak of death as "the great silence", and refer to their homeworld as the "singing planet". The rachni ability to genetically share knowledge across generations makes queens a vast repository of information.