The most terrifying Divine Soul Forbidden Technique in the world is probably the "Nine Death Forbidden."
Once marked by the Nine Death Forbidden,
It truly is... only after nine deaths that a sliver of life arises.
Miles of frost and snow, covering the Heart Lake.
Xie Xuanyi gazed at the character "death" suspended in the mid-sky, a half-drop of Undying Spring spread out within Jiang Huang's Divine Sea, forcibly dispersing the Silent Annihilating intent of this Divine Soul Forbidden Technique... much of the biting coldness of this Heart Lake dissipated, but still, frost and death qi lingered and encircled.
The Nine Death Forbidden is terrifying,
Not because its killing power is tremendous, making it hard for those affected to survive.
But it's because...
The Divine Soul of the affected will endure torture over and over from the assault of death qi, and ultimately completely sink.
Death is not the scariest part; it's giving people hope for life yet making it impossible to die.