The Hidden Sith Army was the massive that Darth Subeth began forming around 83 BBY. He, amazingly, gathered an army of over 850,000 soldiers plus nearly 200 capital ships without the galaxy at large realizing he existed. The army nearly obliterated every city or planet that witnessed the existence of the Sith. Darth Subeth hid the army for twenty years while he trained his whole army and himself. By 63 BBY, Darth Subeth thought his army was finally ready. He found out that a large battle was currently going on at Ris'danon, so the army was brought to this planet, as its defenses were already weakened by the large pirate attack. The Sith won the battle very easily, its size being a huge advantage. Even though Ris'danon had a larger-than-normal army, it was very small compared to this massive Sith army. Ris'danon was conquered by the Sith, but one Jedi escaped to tell the story to the Jedi Council. The next years had many missions against Darth Subeth, but the Sith refused to move from the planet. After many years, the Sith were finally removed from Ris'danon, but they weren't destroyed. They retreated to the Outer Rim, where they repaired their army and began attacking planets so far out (in fact, they were technically on the border of Wild Space), the Republic didn't find out about this. The Sith army grew and grew, and a long time later, they were finally ready to come back into more civilized space.