From personal experience, these drop all 3 recollections and the beryl memosphere on the first floor of Promyvion-Dem at a fairly high rate. Too bad it has only 1 spawn point. Myself and 2 friends got 4 various recollections and 3 memospheres in about 2.5hrs of farming with 1 pop every 15 min.
This guys level is 27-33 because he checks easy for me when I get level capped to level 30. But he did kill me so Its either level 27 or 33. Its checked exactly Easy Prey --> Seems to have high defense with capped Great Sword.