- "Lord Sadic is one of Darth Angral’s most powerful–and power-hungry–apprentices. Born to lower-class parents barely one step above Imperial slaves, Sadic quickly demonstrated a strong will, Force sensitivity and unrestrained ambition. He was the only acolyte of his group to survive the Sith trials on Korriban. Some say this was more than just luck. A string of unexplained murders at the Sith Academy abruptly ended when Sadic finally left Korriban. Initially apprenticed to Lord Umbriss, Sadic served as his master’s personal assassin for several years. That apprenticeship ended the same day Umbriss crossed Darth Angral, who “inherited” Sadic along with Umbriss’s estate and wealth. Although Sadic pledged eternal loyalty to his new master, Darth Angral kept his apprentice on a tight leash. Angral recognized that of all his servants, Sadic was the one most likely to kill him."
- ―In-game Codex (Persons of Note)
- "What's this Tarnis? A loose end? For shame."
- ―Lord Sadic mocks his master's son, Tarnis.
Sadic was born on the fringes of Imperial society, however, a strong Force sensitivity gained him entrance to the Sith Academy on Korriban. He eliminated numerous rivals during his time as an acolyte, and eventually became apprenticed to the Sith Lord Umbriss.
Sadic served his master as an assassin for several years until Umbriss incured the wrath of the far more powerful Darth Angral. As a result, Angral killed Umbriss and claimed Sadic as his own apprentice.
During his tenure under Darth Angral, Sadic was quickly realized as the most likely of his master's servants to eventually become treacherous. Despite such, he rose to the rank of Sith Lord. Lord Sadic also developed an intense rivalry with fellow apprentice Lord Nefarid.
During the Cold War, Tarnis, the son of Darth Angral, infiltrated the ranks of the Republic military and became one of the chief scientists under General Var Suthra, designing the Planet Prison superweapon and gaining access to many of the Republic's other weapons programs as well. "Doctor" Tarnis' creation ionized the atmosphere of a planet, therefore preventing any spacecraft from entering or departing.
In a ploy to hold the entire Republic capital prisoner, Tarnis faked his own kidnapping by the Black Sun pirate syndicate and fled to the ruins of the Jedi Temple. As the Planet Prison entered its activation sequence, Tarnis entered a holo-conference with his father and his fellows, including Lord Sadic.
Unfortunately, a young Jedi Knight intervened, a situation which prompted Lord Sadic to mock Tarnis for his inability to tie up loose ends. He observed as Tarnis engaged and was defeated by the Knight. An enraged Darth Angral swore to avenge his son's murder on the Republic.
Lord Sadic was deployed to Nar Shaddaa, where he seized control of the Republic's Power Guard project. The SIS Agent Galen was captured by Sadic's forces, and he was forced to undergo the Power Guard process and obey every command of Sadic.
Following several interruptions by the same Jedi Knight who had killed Tarnis, Sadic willingly underwent the Power Guard process to gain more power. The Knight confronted the Sith Lord, who was convinced his enhancements ensured his victory. Unfortunately, in a brutal duel, Lord Sadic was killed by his opponent.