2nd day playing and I've completed all of hard except for the literal last boss which I'm stuck on at the moment. I have like 600 energy banked and my Kael atm is 4 stars. What's the best place to use my energy. I'm assuming farm and try and get 3 stars to get Kael to 6 asap, just not sure if any dungeon has better 3 star rates than others or anything like that.