The easiest and fastest place to farm these is at the Keep Ruins Bonfire. I farmed these forever in early game with Fireballs, then I’d fire two arrows at two Elder Ghrus for souls from the far right, then fireball them each by the bridge as they started their return, then shot an arrow at the last one and cleared him the same way, then repeated the whole thing.
Farming was far slower but I did get 30 for the Covenant Wolf Knight’s Greatshield & Wolf Ring, as well as the Old Wolf Curved Sword.
This method is way faster.
1. With your Crystal Sage’s Rapier in one hand and Witchtree Branch in the other, Cast Hidden Body
2. Switch the staff to Seething Chaos and your Pyromancy Flame
3. Run out to the right of the bridge, then face between the first two Ghrus, and throw 2 of the Seething Chaos in their direction (try to cast beyond the first rock)
4. Switch your flame to your +10 Hollow Weapon before they explode
5. Stand near the flames as they explode then grab your drops and return to the Bonfire.
You don’t need any rings other than the Covetous Gold Serpent Ring, and of course that Hideous Mimic Chest on your head.
But some useful rings might be the Sage Ring, the Covetous Silver Serpent Ring +3, and the Lingering Dragon Crest Ring or the Sun Princess Ring.