[How do i factory reset the dark core RGB?]

With the help of my friend and forum member C-Attack, you have to power off the Core Dark RGB and make sure you're on the 2.4 wireless mode. After you're powered off, press and hold both forward and back buttons and leave them firmly pressed. While still holding the forward and back buttons, power the DCrgb. This will factory restore it along with all three HW profiles. Best of luck.