Malachor V is a fictional planet initially developed by BioWare for the role-playing game Star Wars: Knights of the Old Republic and then further developed by Obsidian Entertainment for its sequel Star Wars: Knights of the Old Republic II: The Sith Lords. The ancient Sith colonized the planet and built Trayus Academy there yet abandoned it sometime prior to the Battle of Malachor V.
Revan choose Malachor V as the final battleground against the Mandalorians due to the planet being a taboo in Mandalorian culture. He also sought to use the battle to break Jedi into become Sith loyal to him or her. Revan had Meetra Surik (later known as the Jedi Exile) and Boa-Dur activate the Mass Shadow Generator super-weapon to annihilate the Mandalorians and the Jedi who Revan suspected wouldn't follow him. Arren Kae presumably perished in the battle, and survivors included Meetra Surik and the individuals who would become Darth Traya, Darth Sion, and Darth Nihilus.
The player, as the Jedi Exile, later confronted Traya and Sion at Trayus Academy.
The world is taboo to Mandalorians – we only came here when the Republic fleet gathered, and we knew it was our only chance to stop them.— Canderous Ordo, in Star Wars: Knights of the Old Republic II: The Sith Lords (cut content)
Observation: Master, that was the lesson of Malachor. Any Jedi involved in the systematic slaughter on such a scale cannot help but doubt and question themselves.
Clarification: Whatever it is called, master, it seems to be quite a vulnerability. Revan even admitted as such.
When a Jedi, or any soldier, suffers doubt, it weakens them. With the Jedi, however, it is more pronounced, since they are extreme examples.
That is why Revan felt that Malachor V was so important. It was intended to be a conversion tool.
Observation: Master, I do not believe that the Mandalorians were the true target at Malachor – I believe that the intention was to destroy the Jedi, break their will, and make them loyal to Revan.
I do not know if you examined the records of the deaths on Malachor, but you cannot escape that many of the Jedi and Republic soldiers who died were not Revan's strongest supporters.
Observation: I believe that Revan was "cleaning house" at Malachor V. What ones did not die became Revan's allies against the Republic.
Assessment: When faced with a continuous series of hard-fought battles, I detected a significant statistical increase in Jedi following Revan over the Jedi Code – a compromise in principles brought about by battlefield conditions.
The emotional weight of war changed Jedi morale, power, and eventually, their allegiance.
Conclusion: I believe the Mandalorian Wars were to beat the Mandalorians and also to allow Revan to build the foundation of his army.
When the Mandalorian invasion came, Revan seized the opportunity it presented. Many Jedi flocked to the Outer Rim to follow the charismatic young Knight… and many fell under the sway of the dark side.— Vrook Lamar, in Star Wars: Knights of the Old Republic
- "Malachor V" entry at Wookieepedia