Whoa, this is some kind of landmark. I feel like there ought to be a fanfare or something.
Oh, here we are.
991. Sikan. The Sikan (singular Sika) had their planet invaded during a crisis by someone else that I haven't covered because they didn't have an article when I originally went through the "C"s.
Rating: 1/5. Yeah, I don't know, there's no real incentive to be interested here.
992. Sikurdians. Sikurdians are rather hilarious-looking entities, with earthworm-shaped tentacle-arms and tentacle-legs. They like axes, and one infamous one is known as Alabar Double Ax.
They seem to be fairly small, in the three foot range.
Rating: 3/5. I kind of like their appearance.
993. Silentium. The Silentium are "descended" from droids created by a starfish-shaped species. That species died untold ages ago from a supernova's radiation storm, but the droids would go on to transform thousands of their members into massive fifty kilometer diameter spheres.
Okay, just for reference, the first Death Star is 160 kilometers in diameter, and the next largest Imperial warcraft I know of is less than twenty kilometers long. The majority of such craft the Empire commanded were rare, and the ships the Empire had in large numbers were far less massive.
The Galactic Empire is among the most powerful civilizations in all of fiction, and the Silentium probably outgun them. (They also likely outgun the next dozen most powerful civilizations after the Empire put together.)
Apparently, though, the Silentium are relatively pacifistic, outsiders to the wider galactic civilization (in fact, they're from another galaxy originally), and didn't want to get involved in galactic politics directly.
In the past, the Silentium were at war with the Abominor, another extragalactic race of droids that could rival planets in size, and the massive war between them inspired a deep cultural hatred of droids and other traditional technology in the Yuuzhan Vong.
The Silentium are very much beings of order, and were worried about their own stagnation, being super-orderly and essentially immortal. In order to shake up their own society, they took one of their smaller-model units based on their masters and programmed it to observe society and obey the rules of regular droids. Their intention was for this droid to experience society for a few hundred years this way, eventually bringing it back to themselves and then experiencing galactic society vicariously through its memories.
However, upon application of logic to what they had done, they realized that the droid they'd created was essentially a child of their own kind, and so they rushed in immediately and, in the only demonstration of their might before galactic civilization at large, stopped an Imperial task force and rescued the droid, the companion of Lando Calrissian known as Vuffi Raa. In the process, they somewhat unintentionally also rescued the Oswaft from extinction.
They haven't had any real roles in fiction beyond that, but are also responsible for things akin to alien sightings throughout much of the Star Wars galaxy.
The Silentium are beautiful.
Rating: 5/5. If I had to pick a single Star Wars race as my very favorite, the Silentium would be serious contenders, and they're almost definitely in any top five I'd create.
994. Silika. The Silika are "multiple-armed" (...guys, two arms are multiple arms; please be more specific) rock creatures (as their name suggests, silicon-based). They apparently are intoxicated by mineral water and have a very strict honor code.
Rating: 4/5. ...I like rock people, especially whimsical ones. (Discworld trolls have to be one of my top ten or twenty fantasy races.)
995. Siniteen. Siniteen (which is an anagram of "Einstein") are large-brained beings who look like their brains are visible on the outside. As a result, Siniteen often are known by names such as Brainee and Pons Limbic.
They are known for being able to perform complex calculations, including hyperspatial jump calculations, in their heads.
Rating: 3/5, mostly for humor value.
996. Sinkars. The Sinkars are apparently a slow-moving, slow-thinking species that rumors variously claim to be mindless beasts or extremely wise, long-lived sapients with telepathy. Rumor also claims that they feed only on the local sludge and solar energy, or that they can drain starships and even living creatures of their energy if they get too close.
They are also described as "helium-based slugs," yet also described as resembling gigantic amoebas. They live on a world where oxygen snows out of the sky.
Rating: 3/5. I like the mysteriousness of it.
997. Siolans. A Siolan can recognize close relatives by scent.
Rating: 1/5. That's interesting, but common enough that I'm not sure it qualifies as special in any way.
998. Sipsk'ud. Sipsk'ud are duck-billed, probably penguin-shaped sapients with seven eyes arranged in a circular pattern (one in the center and six surrounding it). They apparently don't live in the same kind of atmosphere as humans, for they apparently wear spacesuits when coexisting with humans. The known member of the species was a pilot.
Rating: 3/5. I like the combination of conventional animal features with a weird eye configuration.
999. Sith. The Sith, also sometimes known as Red Sith or Sith Purebloods, are the race whose name became all but synonymous with the dark side of the Force. They invented multiple dark side traditions (Sith alchemy, Sith magic) and ruled an empire during the early history of the galaxy. They have/had at least three castes/races/subspecies, the Kissai, Massassi, and Zuguruk. (One of these names is not like the others...) The majority of the Sith possess(ed) Force sensitivity, and even exist(ed) in a more strongly symbiotic relationship with the dark side, supposedly being at least partially sustained by it and being unusually strong in it. (Presumably, this is somehow connected to their encounter with the Rakata.)
The reason I talk about them in an inconsistent tense is because as far as anyone knows, because of a human Sith organization instituting an interbreeding program with the Sith Purebloods, the original Sith are probably extinct or have gone into hiding (nobody's sure which). For instance, one group of Sith refugees would eventually become known as the Sorcerers of Tund (they're probably extinct, since their last, non-true Sith member, the Croke Rokur Gepta, took credit for exterminating the rest of them-note the Lando Calrissian Adventures link in the Silentium entry).
They were responsible for a lot of old, mysterious things that modern (movie-era) inhabitants of the Star Wars galaxy aren't necessarily aware of as their handiwork; for example, the massive temple buildings on Yavin IV in A New Hope are actually special Force-amplifying buildings left behind by the Massassi and the human Sith Lord Exar Kun. There's also a region of 120 or so planets that are or were known as the Sith Worlds; the region also contains three worlds that have been credited as the Sith homeworld, all of which are strong in the dark side. (Korriban is apparently the real homeworld, which they abandoned and turned into a sort of tomb world; the world of Ziost was adopted later on, while Dromund Kaas's status as an apparent homeworld is "possible propaganda".)
While the Rakata taught the Sith about the dark side, the Sith king, Adas (who was over three hundred years old at the time and was the first king to rule the entirety of their original homeworld) was able to anticipate the inevitable Rakatan treachery and was able to drive them off at the cost of his own life. From the fact that there were multiple Sith Empires, several of which were ruled by the Red Sith themselves and most of which were very influential in galactic politics if not the dominant powers of their times, it's fairly obvious that they were at one time very influential.
When all is said and done, the Sith are basically Evil Ancient Egypt IN SPACE. That's honestly pretty fun.
1000. Sivorians. Native to Sivoria.
Rating: 1/5. Get outta here, ya bums! (It's very true to form that one of those would be where I hit four digits.)