The Dark Heart Seed came from the Ball of Ice Soul and Dark Eye Incomplete Page.
This Dark Heart Seed will control your every action and even your thoughts. You can’t escape my mental energy senses within a ten-thousand-mile radius
The Dark Heart Seed Zhao Feng used was similar to the Ghost Mark set on him by the mysterious skeleton, but the Dark Heart Seed that was used through the God’s Spiritual Eye was more powerful.
Zhao Feng could even make the Dark Heart Seed explode and bring disaster upon Lin Tong if he wished, as long as he was within a certain distance.