Alrighty then. Alien species coming up!
Name: Yuan-ti (Because I love the D&D name too much, tee hee)
Appearance: Almost completely serpent with two arms and standing around 7 or 8 feet tall. Scale colors range from green to black, sometimes red, and their faces are slightly humanoid but still very snake-like (unblinking eyes, forked tongue, fangs). Most Yuan-ti are not venomous but one subspecies, the Yeshnaks, are highly venomous and are more physically enhanced than other Yuan-ti.
Government: The Yuan-ti are ruled by a monarchy from a royal family line that has been unbroken for almost two thousand years. This line is the line of Yantar, the same name as their home planet, and are entirely Yeshnaks, having used their venom and increased strength to stay in control. Most laws boil down to "Don't cross the Royal Family or die." There are no prisons, all crimes are punished by immediate execution no matter the severity and as such, the crime rate is considerably low. When a child of the Royal family reaches 3 years old, they are immediately taught the arts of assassination, stealth, and all forms of combat, making them formidable rulers and often executioners. When dealing with other races, the Yuan-ti rulers have the appearance of kindness and courtesy but everything they do is for their own gain. Rulers of the Yuan-ti have been renowned as having silver tongues and honeyed words that let them manipulate almost all other species and governments, if they wish. Empires have been puppets of the Yuan-ti or destroyed by enemies driven by Yuan-ti words. When confronted the Yuan-ti will make the appearance of giving in before they strike with deadly and almost unstoppable force. But unlike other governments, the Yuan-ti do not wish to conquer or enslave due to their total disdain for other races, even if they were slaves, and have remained a powerful force in the galaxy/universe but have not assumed total control.
History: For centuries, the Yuan-ti were constantly at war with each other, leading to stunted technological growth until the Yeshnaks, lead by the first Yantar, gathered an army so powerful they nearly wiped all the other Yuan-ti out of existence. But instead of destroying them, Hesstash Yantar decided to bring them under his rule and unite the Yuan-ti. After a century of rebuilding and mistrust, the Yuan-ti finally accepted each other and their new rulers, bringing and unheard of era of peace to the newly named planet of Yantar. After that the planet exploded with technological advancements and new ideas, reaching out into the stars a matter of centuries after they were united. Their first contact with alien species did not go well, it started the first interplanetary war the Yuan-ti had ever conceived of. After decades of bloodshed and ruthless violence, the Yuan-ti were victorious and Maktas Yantar decided that the price was too high and other races too foul to continue conquering the galaxy. Thus, the Yuan-ti helped rebuild the civilization they nearly destroyed and took the stance of diplomacy with all other aliens they encountered, using their intelligence and deceptive charm to make a place for themselves among the most powerful governments. For the first few centuries of interplanetary contact, the Yuan-ti went unchallenged but when a royal convoy carrying the Crown Prince was attacked by another species, they retaliated swiftly, fiercely, and decisively, bringing other governments into the war on their side and eliminating the propaganda of their attackers, effectively cutting the enemy army in half and decreasing the quality of soldiers. The Yuan-ti soldiers fought with cunning and struck every weak point, crippling their enemies food supplies and the moral of the population to force them to surrender within a few years Ever since then they have been feared and respected by all, and Yuan-ti mercenaries are the most valuable to any government or organization.