Bahamut, Magus Sisters, Anima, Alexander, Knights of the Round and Odin were some of the most powerful, but in certain games we saw much weaker versions. Odin dying to Seifer was stupid silly, and I refuse to believe it happened. The Magus Sisters were far weaker in FFIV than they were in FFX too. Knight of the Round was godly in FFVII. Alexander was awesome in FFIX, yet nothing all too great in other games. I suppose it depends on the game. I love Ifrit, Shiva and Ramah but all three of them are nothing to brag about when compared to some of the ones we have seen in these games.