But now the Terran Commonwealth has got a problem.
About eighteen months ago an exploration ship on the spinward frontier of explored space was destroyed, it's wreckage was found a couple months latter as radioactive slag while unscheduled jumps were also detected. Another was lost in the same area a few weeks after that. After that they began pairing up survey ships and in a month's time they managed to survive the attack, which was launched by a 250 meter long warship of unknown make and model. Before said attack it was hailed with a standard first contact package. The craft responded announced itself with a basic video transmission showing an image of a bridge of said ship in which an individual of this species...
![Image](https://img00.deviantart.net/1e31/i/2017/293/4/5/alien_warrior_caste_officer_by_imperator_zor-dbr7495.jpg)
...ranted on in a language that humans could not understand, though certain visuals that were sent along with the transmission such as one of their four fingered hands grasping a model of the star system, a parade with millions of these creatures marching in lockstep brandishing swords in front of a pyramidal keep as twelve members of their species watched and a pair of such creatures clashing their swords together conveyed conveyed some of their intent. A week latter six of these ships attacked an exploration fleet supply dump which was (just) fought off by the commonwealth navy squadron assigned to guard it, even though it lost it's cruiser and two of it's destroyers with an exploration ship receiving significant damage. A long range scouting mission was then organized in the general direction of the attacks with several ships and warships which found about 600 light years from sol radio traffic as well as several inhabited worlds with phase one colonies being developed as well as having dozens of ships. Observations were made and an attempt at proper first contact was made with a data package being sent out containing relevant information on humanity and our general history. This was incidentally not met with hostile intent beyond a couple of ships flew over which did not fire but did relay a language package, some information and a general message that this ship that they are in their territory without permission and should leave.
What can be acquired of the information gathered is that this species (the Dreivan) is organized into an Empire that has colonized an area of space about 200 light years in diameter and lays claim to an area about 400 light years in diameter. Their society is largely feudal and has a religion which stipulates that those who fight have a right to rule. There are several castes, which include warriors, attendants, artisans, merchants and laborers as well as an enslaved caste of untouchables. Their society has twelve great clans, each one with it's on hierarchy of vassalised lesser warrior clans under their control. The leader of each of the great clans elects from their own ranks an emperor who serves for life or until he voted out by eight or more clan leaders. Warriors are required to be trained in warfare and serve for 3.52 years in the military before going into either a religious, military, police, educational or civil service career and are required to take up arms afterwards when summoned to duty. About 5% of warriors who don't cut the mustard are drummed out and become part of the civilian castes (usually the attendant caste or merchant castes). The Warrior Caste makes up about 3% of the Dreivan population. It is possible for a civilian Dreivan to become part of the warrior caste by serving for 21.12 years, those that do enter the lowest tiers of the warrior caste though outside of major wars there are only a limited number of slots. The same could not be said about the 17% of the Empire's population which are not Dreivan. Like humans, the Dreivan encountered several other sapient races at a more primitive level of technological development, which they conquered and enslaved. 91.7% of these conquered races are chattel slaves with the rest existing as an underclass of slave drivers that are still reckoned to be below any free Dreivan. The total population of the Dreivan Empire is 135 billion and it controls about 101 worlds.
Small scale limited warfare is part of life for the Dreivan Empire. The military forces of the Empire is half divided among the Imperial Military and half is divided among the clans. The house which launched the attacks on the scout ships was a rival of the clan that first contact was made with. Each of the clans has it's own army and naval assets. Clans often fight with each other for trade concession, positions within the hierarchy, control of territory and similar. In part this is done to dispose of old warriors since it is considered disgraceful for a warrior to not die in battle. These battles are usually scheduled at pre-determined battlefields in accordance to strict rules. Most of these are done with traditional weapons such as swords and muskets though some have more modern weapons and clashes between the big clans can involve spacebattles. In total the Empire has about 20,736 warships between 150 and 1,200 meters long and it could easily mobilize over two and a half billion ground troops.
Dreivan technology is a bit behind Commonwealth tech. Their reactors generate about 5% less energy than a commonwealth reactor of comparable size, their shields are 30% less effective per watt and their hyperdrives can only reach 512 C rather than the 1,032 C that Commmonwealth Hyperdrives can (in both cases this refers to high end hyperdrives used by exploration ships, courier vessels and warships, most civilian freighters, transports, construction ships and similar on both sides make do with cheaper models which can go half as fast). Their ships and torpedoes are not as fast accelerating (10 g vs 12 g for torpedoes, 4.6 g vs 5.4 g for ships) as their Terran counterpart and while their lasers are as powerful their rate is lower. In general in a firefight a Commonwealth frigate/destroyer/cruiser has an advantage in strategic maneuverability and a minor advantage in a shooting fight over a comparable Dreivan ship, though this advantage is hardly overwhelming.
They do have shield networks above their more prominent worlds and theater shield generators for all their cities. Dreivan ground forces have tanks, artillery, air support and similar. Most (91.7%) of their infantry is unpowered (though the average Dreivan is about 2 meters tall and has upper arms three times as strong as an average human's arms) though they are equipped with personal shield generators which can on full power take a few shots from a Commonwealth Powersuit rifle before going down. They also all carry monomolecular swords of starship armor grade molecular alloy such as the one pictured before.
Hyperdrives take about 30 minutes to spool up to jump. In relative space terms you can't get too close to a large gravity well (for Sol this is about 22 AU). Attempting to do so will cause your ship to be spewed out across the surrounding few hundred million kilometers as a cloud of radiation and mono atomic dust. Minor gravity wells from meteors and small asteroids cause minimal distortions and even if a ship in hyperspace flew directly through the corresponding realspace of said object it would have no effect on either object. Ships jumping in and out of Hyperspace (and their general size and mass) can be detected by FTL sensors up to a lightyear and a half away. Both Commonwealth and Dreivan Empire ships have that technology.
There Opinion on the Commonwealth is divided. They have some information collected from salvaged computers. Some houses want to mobilize a conquest fleet right away, others desire to scout out the situation before making the move. Preparing a conquest fleet would take a few years and it would mean establishing logistical hubs along the way to refuel and provision their armada which would take more than a year to go from the outskirts of their Empire to the fringes of Commonwealth space. Since the first encounter some 300 more warships have been ordered (of which 200 have been delivered) and it has been estimated that the Commonwealth could produce up to 1,000 warships a year with a peacetime economy (an output which could be expanded by 50 ships each year) and 2,000 a year with a wartime economy.
What do you do?
Zor