Soul Master

"The King falls, but I live forever!"

- Soul Master

Soul Master is a major antagonist and boss in Hollow Knight. He was once the leader of the Soul Sanctum, who tried to use the power of soul to immortalize himself to live through the Infection, but was ultimately driven mad from misusing the substance.

History
During the time of the Infection caused by the Radiance for the neglect in her worship, Soul Master and his students studied collecting soul from within the bugs' spirits, believing collecting enough would stop the Infection. The Pale King opposed Soul Master's idea and ordered him to cease his experiment, although Soul Master continued to perform the experiment in secret from both his students and the Pale King.

When the Hollow Knight managed to seal away the Infection, everything seemed to return to normal, but it did not last long for the Infection to find its way out of its sealed state. Without the Pale King's advice, as he and his White Palace vanished following the Hollow Knight's sealed fate, Soul Master and his followers took more drastic measures to obtain soul by conducting experiments on various bugs of Hollownest to deprive them of their soul, believing enough will grant them immortality from the Infection's wrath, although most of the members were cursed from the misuse of soul and turned into creatures known as Mistakes and Follies.

By the time the Knight makes it to the Soul Sanctum in the City of Tears, they were too late, as the Infection had made it through the sanctum and possessed each and every member of the facility, including Soul Master himself, who faces the Knight at the end of the sanctum.

Due to all of the soul that Soul Master had obtained, he was a powerful foe for the Knight to handle, although the Knight managed to find a way to conduct and collect soul, and used their power against the Soul Master, seemingly destroying him and exposing his soul. Before the Knight was able to collect it, Soul Master managed to recreate himself through his exposed soul and continued his brawl against the Knight, but was defeated yet again, this time for good. The Knight once again collects Soul Master's soul and obtains the Desolate Dive spell, allowing them to slam through the floors of the Soul Sanctum and continue on their quest.

Optionally, the Knight can return to the Soul Sanctum and use the Dream Nail on Soul Master's corpse and enter the Dream World and fight Soul Master's Dream Boss counterpart, Soul Tyrant. He is one of the five bosses that can be re-fought in the Dream World, the others being False Knight, Broken Vessel, Dung Defender, and Zote. Defeating Soul Tyrant grants the Knight 300 Essence to their Dream Nail.

Trivia

 * Soul Master is the only boss to give the Knight a spell after defeat. That spell being Desolate Dive.
 * Prior to update 1.0.1.3, Soul Master's slam attacks did not produce shockwaves.
 * It is possible that the Radiance was the cause of the prophetic dreams that Soul Master was inspired from.