It kinda sickens me that we have to wait for pet mana or buy them with crowns. A good idea would be pet mana wisps. You only get + 3 or + 4 from them, and you rarely see them, kinda like the treasure chests.
Pet whisps might work. We might be able to get away with having them in monster areas and make them as rare as the blue wisps found in those areas. We only get one pet energy point per ten minutes. If people could change relms and farm yellow wisps they would. You would probably need to lower the yellow whisps restore to one energy point per whisp.
I do like the idea of yellow whisps. I hope you can get KI to like the idea too. Good luck!