Monster-Slayer

The Monster-Slayer was a Sith of Sith Legend.

In the legend, The Monster-Slayer duels with rival Sith, The Dreamer. The duel ends with the death of both, overwhelmed by the vapors of the Pits of Paxxis.

According to Luke Skywalker, the legend was rooted in fact, and took place circa 3400 BBY.

At some point, a depiction of The Monster-Slayer's duel against The Dreamer came into Skywalker's possession, which he annotated sometime after the Emperor's death in 11 ABY along with a copy of The Jedi Path and Book of Sith.