Yea the mephit (Palumak?) and thirsty are the chests you can get the bloodstone in. It drops more frequently in the mephit chest. Pulled 2 there so far (in 2 years of trying). I run it til I get both chests 5x then wait for reset. Do it every week.
Thirsty chest pops a lot less frequently.
Spell storing ring drops in the general's chest (edge of map, last chest on desert side). I've gotten one of those.
Keep the faith. You'll get one eventually. It pays to roll up a wizard or sorc alt to do this farming with ;-p 5 minutes per run, if that.