Originally Posted by
Zirusianna
Dickwraiths will always get the most invades. Though keep in mind you can just use Cracked Redeye Orbs, for the same effect, in any covenant.
Gravelord is probably the slowest invaders there is, since you only get invades if you gravelord someone (Which means GFWL has to not be a bitch, and you need to find a guy in NG+ to invade), and keep the connection online long enough for him to find your sign (which you don't want anyway), so he can invade you.
I would say, for who does invades the fastest, it would probably be:
Dickwraiths (Or Cracked Red Eye Orb) > Forest Hunters > Dorkmoon > Gravelord