Da Soocha V was largely covered by kilometer-high jagged, stone spires created by ancient volcanic eruptions and was thus nicknamed "Pinnacle Moon" by the New Republic. The moon's sole native sentient species were the small winged Ixlls. Da Soocha V was also home to the predatory tumnors which preyed on the smaller Ixlls.
During the Galactic Civil War, the obscure Cyax system was scouted by Rebel Alliance scouts who discovered the ocean world of Da Soocha sometime around the Battle of Endor. In 10 ABY, after the Invasion of Coruscant and subsequent Imperial Civil War forced the New Republic to abandon Coruscant, they established a command base on Da Soocha V due to its relative obscurity.
New Republic forces at Pinnacle Base
The primitive Ixll natives were fascinated by the arrival of the New Republic staff, particularly because their starships frightened away the large winged predatory tumnors which had previously preyed on young Ixlls. To establish the base, New Republic engineers cleared and expanded the caverns within the immense stone spires to accommodate hangars and operation decks for the vessels of the New Republic Navy.
After Jedi Master Luke Skywalker was captured and brought under the influence of the Reborn Emperor Palpatine, the Emperor arrived above the moon in his Eclipse-class dreadnought Eclipse accompanied by a small flotilla of vessels. Palpatine's fleet caught the weary New Republic defenders off-balance and the Emperor was able to make his demands unchallenged. He demanded that Leia Organa surrender to him and board his vessel, something she did willingly, as he still held her brother, Luke Skywalker, under his influence.
Attempting to break Organa and bring her unborn child under his influence, Palpatine goaded Skywalker into attacking her and prove himself still worthy of following the way of the dark side. Reaching out to his lingering good side, Leia managed to bring Luke out of his mental captivity and the Jedi Knight attacked his former master, only to provoke the Emperor into unleashing a Force storm that began to devour the Republic's fleet.
Using the Force to counterattack, Luke and Leia weakened Palpatine's power, sending the storm out of control and causing it to devour Eclipse. The Skywalker siblings made it out of the ship as it tore apart in a shuttle. At the time, it was believed that the Emperor was destroyed aboard his capital ship.
The destruction of Pinnacle Moon.
Following the New Republic attack on Palpatine's citadel on Byss and the escape of the surviving Rebels into hyperspace along with a group of smugglers, Palpatine gave the order for the Galaxy Gun to launch its first world-destroying projectile against the New Republic command on Pinnacle Moon.
However, due to the presence of spies on Byss itself, the New Republic forces along with some of the native Ixlls managed to escape the doomed moon in a fleet of transports. Despite efforts by Luke Skywalker to destroy the missile using the weapons systems onboard his transport Jedi Explorer, the projectile collided with the crust of Da Soocha V and unleashed a nucleonic chain reaction which wiped out the moon in a single flash and effectively wiping it off the face of the galaxy.
In Star Wars: Dark Empire II, the moon is erroneously referred to as Gla Soocha V. However, the PC game Star Wars: Rebellion offers "Gla Soocha" as a common alternative for the planet Da Soocha, suggesting "Gla Soocha V" may be a similarly used alternative.