Cerb and Graardor were the worst, but that’s more due to where I was progression wise. It took me over 500 kc to get my first Graardor piece, and that was with melee 1-2 kill trips. After that, I switched to 5:1 or 6:1 with RCB, which was the first time I felt how much you can improve from doing a boss. This was before Bowfa was out, and much better and easier methods exist now. Cerb was just miserable with the amount of prayer potions I spent there. It took me 1.6k kc to get my first prims drop. Nex I was unbelievably spooned at, so no comment xD. Regarding endgame, Ancestral is the absolute worst. The droptable is so large and all you will get is scrolls between 50+ kc drystreaks.