Soul Master

A boss in the Soul Sanctum. The Soul Master was the head of the Soul Sanctum. He hoarded soul hoping to stave off Hallownest's affliction, but eventually became intoxicated by its power.

Hunter's comments
"The bugs of Hallownest tried all kinds of rituals and prayers to rid themselves of the infection. But to no avail! Perhaps the infection came from somewhere deep inside of them that they could not escape."

Battle strategy
The Soul Master behaves very similarly to a Soul Twister in battle, floating in the air and erratically teleporting around the battlefield. However, he has a wider variety of attacks. The best way to deal with the Soul Master is to stay at the right side of the arena. This will make his floating attack completely harmless (as the Soul Master will always teleport away just before impacting the wall) and make it so that you only need to worry about the shockwave from the Desolate Dive rather than the impact itself.
 * Shoots a semi-homing orb of Soul at the Hollow Knight, identical to the Soul Twisters and Soul Warriors. Can be dodged by jumping if the Soul Master is far, or by dashing out of the way if he is floating nearby above the Knight.
 * Rushes from one side of the arena to the other, trying to smash the foe with his massive bulk.
 * Floats from one side of the arena to the other, surrounded by a shield of four orbiting soul projectiles.
 * Teleports above the Hollow Knight and performs the Desolate Dive, slamming into the ground and creating an immense shockwave that must be jumped over. At times, he will cancel his ground slam into another teleport just before impacting, with the intent to lure the Knight into jumping too early.

After taking enough damage, the Soul Master will appear to die, leaving his signature spell, the Desolate Dive. However, before the Knight can absorb the spell, the Soul Master reappears, breaks the ground and the battle enters its second phase. In this phase, the Soul Master only has two attacks, which it will alternate. This phase is overall significantly easier than the first phase due to the predictable nature of the Master's attacks, the lack of shockwave on his Desolate Dives, and his openness to attacks during the projectile phase.
 * The Soul Master uses several Desolate Dives in quick succession, but without the shockwave. It will still sometimes try to fake out the Knight with a teleport-cancel, but since the lack of a shockwave eliminates the need for jumping, this attack can be dodged easily just by dashing around.
 * The Soul Master will float in place, vulnerable to attack, while soul projectiles materialize at random around the room and are launched at the Hollow Knight one by one.