Xenos - Xenos Interactions with Humanity: It is not recorded exactly when the Human race learned that it was not alone in the galaxy, or which intelligent alien species it first made contact with, but what is known in early Imperial records is that Humanity has been competing with xenos since the Age of Technology.The first Human interstellar civilisation which existed at that time made contact with many alien races, possibly including the Aeldari and the Orks, but the majority must have been hostile or incapable of co-habitating with Humans as no aliens are known to have ever willingly integrated into the broader interstellar Human civilisation of this time.When the Age of Strife began in the 25th Millennium with the collapse of the first Human interstellar civilisation, many suddenly isolated Human colonies were set upon by all manner of hostile aliens, though a few notable exceptions of peaceful coexistence occurred as well.The scattered outposts of Mankind would be preyed upon for many Terran millennia by various xenos species, pushing the Human race towards eventual extinction until the Emperor of Mankind revealed His existence and began His galaxy-spanning Great Crusade to reunite Humanity under a single interstellar government.The Emperor believed that only in unity -- unity bought at nearly any price -- could Mankind survive a galaxy that was far more dangerous than any Human scholars of an earlier age would have believed.At its inception, the Imperium of Man made one of its core objectives the extermination of all alien life forms that posed any threat to Humanity. Thus many species suffered extinction at the hands of the newborn Imperium which perpetrated one act of genocide after another. This would also apply to the majority of Human civilisations encountered during the course of the Great Crusade like the Interex and Diasporex, which had founded cultures where alien and Human populations had successfully integrated into a single whole.Diplomacy was rarely tried, and was more often offered only to other Human civilisations encountered in the course of the Great Crusade. Certain aliens, such as the Aeldari, who were more technologically advanced than the Imperium were often simply left alone so long as they did not threaten Human interests.The Imperium of Man's extreme xenophobia and outright call for genocide against all other intelligent species in the galaxy is in some ways justified by the sheer hopeless belligerence of most xenos races encountered since the Great Crusade.Almost all alien species encountered by Humanity since the Emperor first began to push His forces out amongst the stars have been so malevolent or aggressive toward Humanity that any form of negotiation or parley often proved impossible.Other instances, such as during the Imperium's first encounter with the Human-alien alliance known as the Diasporex, would end in violence because of the inherent distrust the Imperium had for all alien civilisations even if there was common ground that could be found.This policy of unconditional hatred persists into the present-day Imperium more than 10,000 standard years after the Great Crusade ended in the blood and fire of the Horus Heresy. In that time, many more alien civilisations have been discovered and destroyed regardless of threat level, culture, disposition, or technological advancements.These sentiments of xenophobia have been reinforced by the Imperial Creed propagated by the Adeptus Ministorum, which preaches that Mankind has a divinely-inspired manifest destiny to be the sole ruler and inhabitant of the galaxy. Humanity alone, the Imperial Creed teaches, is the sacred form of intelligent life chosen by the God-Emperor to spread out amongst the stars. All other intelligent life is to be reviled as an abomination and an affront to the God-Emperor's plan for Humanity.Much of the Imperium, led by the religious fervour of the Adeptus Ministorum, believe in the extermination of all aliens, even those that are entirely peaceful species. When the Human masses are stirred to such fear and fanaticism, they demand destruction over any kind of cooperation or coexistence.This might seem like a harsh measure, but the 41st Millennium is an age where ignorance is a virtue and brute force is used to solve a multitude of problems; the dangers of failing to act are too unthinkable to elicit any other response. It has not become this way without reason; most aliens encountered by Humanity are hostile and devious, and some have proven as ruthless and ambitious as Humanity itself. To them, there is no room in the galaxy for the Imperium.Despite the many xenos dangers across the Imperium, there are those who, in their ignorance or desperation, are willing to make pacts with aliens. Sometimes this is seemingly innocuous: trading to gain advanced technology, hiring brute labour or buying mercenary help.So, concealed within teeming Hive Worlds, xeno-tech draws high prices in illicit markets often called the "Cold Trade," while the carnivorous Kroot have been paid in flesh to fight alongside Human Planetary Defence Forces.In the Tollovian Cluster, fickle Caradochians are not only tolerated, but allowed to sell their military services to the highest bidder. In this way, many argue, Humanity is tainted. After all, accepting a Donarathi amongst our own kind is only a small step away from making open covenant with the Hrud, the Ork, or any of the other foul alien species that plague the galaxy.