You want to raise your rank in the Blades of the Dark Moon covenant? Tired of killing 300+ silver knights in Anor Londo? Follow this easy guide to get your Proofs of Concord Kept without even breaking a sweat.
The Secret is Patience
I have been grinding Proofs of Concord Kept for hours, with very little to show for it. However, I left my game open for a few hours while I was AFK and I earned all the Proofs of Concord Kept I could ever want.
So, join the Blades of the Darkmoon Covenant and go to Anor Londo or wherever really (you have a better chance of being summoned if you are in the same region as the Host, but you can be summoned anywhere after a certain amout of time). Then make sure the covenant sign is pulsating which mean that you are able to be summoned. Then just Alt-Tab out of the game and watch some Netflix or Youtube, you have nothing to do now. Getting summoned happens rarely, but when you aren't sitting there waiting for it to happen it doesn't appear to take as long. Then when you are summoned you are AFK so you have about 50% chance of having the ennemy phantom defeated without you even moving a finger. Then when the phantom is defeated and you return to your world you will be eligible to be summoned again without you having to do anything. Leaving the game like this overnight could easely give you all the Proofs of Concord Kept you'll ever need on a character.