The Axeman killed Fiona in "Go to Hell," paving the way for a test to decide on the New Supreme. Zoe, Madison, Queenie and Misty are the four contenders laying the claim to the crown of the Supreme. Zoe, Madison and Queenie have started displaying multiple-new-powers, making each witch believe that she is the New Supreme. It is highly unlikely that the exercise to find the New Supreme will be a peaceful one.
The final episode of "American Horror Story-Coven," "The Seven Wonders," will reveal who is going to take the place of Fiona. The previous episode described 'The Seven Wonders' as "seven acts of magic so advanced [that] each pushes the boundaries of craft into art." These seven acts are Telekinesis, Concilium [mind control], Transmutation, Divination Vitalum Vitalis [balancing of scales between one life force and another], Descensum [a perilous descent into the nether worlds of afterlife] and Pyrokinesis.
"Every generation needs its leader The Supreme. No simple test could ever determine the sovereign among us. We rely upon seven: 'The Seven Wonders'," according to one of the captions of the previous episode.
All the four, Zoe, Madison, Queenie, Misty, now want to wear the Supreme's crown. Here is a brief analysis of these four contenders.
Misty brought back Madison to life. Madison interred Misty alive. Madison has turned dark in her bid to become the New Supreme. Her heart murmur has gone and she can control her mind to cause havoc. Also, she has the power to transport herself from one place to another. If Madison turns out to be the New Supreme, she might turn out to be worse than Fiona.
In the previous episode, Queenie travelled to her personal hell and came back. She also had saved Marie and killed Henry by pulling the trigger of a gun in her mouth. In the previous episode, Queenie brought back Misty to life, revealing her power to give life. If Queenie is crowned, she is likely to struggle as the new Supreme.
Myrtle had asked Zoe to elope with Kyle. She had done exactly that. However in the previous episode, she returned to the academy, deciding to embrace her destiny as a witch. She, too, resurrected a dead man who was killed by Kyle. Zoe is a lot like Cordelia. As the new Supreme, Zoe is very much capable of leading "the way out of an era of strife and chaos, towards repair and rejuvenation."
The swamp witch, Misty, has resurrected a number of dead people, including Myrtle and Madison. In the previous episode, she showed her brawn power, as well. Myrtle had presented her as the next Supreme, which triggered Madison's hostility towards her saviour. Misty, however, does not come across as a serious contender. If she becomes one, there might be a lot of singing and dancing in the academy.
It is not unexpected if Fiona comes back to life, revealing that she was never fed to the alligators. If she turns-out alive, she is very much capable of slaying all the witches. At the end of final episode, Fiona's reign as The Supreme might continue.