One reason why shouldn't keep so many dead creatures in your lab: they can help a neromancer escape.
From saint to demon in 30 seconds.
Martinet catches Rita sneaking around in his lab, but Rita escapes by distracting Martinet with all the dead fishes he's been keeping in jars. Later in Anati, Jeanne is set to be burned at the stake. Some of the citizens try to charge the execution grounds to rescue Jeanne, but Charioce orders the knights to cut them down. The fire is set and Jeanne watches the chaotic scene unfolds and sees some hallucinations made by Martinet telling her that the angels were just using her. Martinet's drink appears in front of Jeanne and Jeanne drinks the liquid, which causes her to turn into a demon. Jeanne frees herself, summons the god-killer sword given to her by Michael, and then summons a large winged demon to fly away. Bacchus watches the whole thing from the crowds, and then he is approached by Rita who wants to ask him some questions.
Can somebody shut this guy up?
Meanwhile, Amira, Kaisar and Favaro follow the GPS necklace location to a valley, but suddenly all the rocks starts floating in the sky and giant demon flying squid fortress appears. Martinet and Belzebuth appear and trap Favaro and Kaisar in coffin-shaped force fields. Martinet explains that he and Belzebuth were the ones who made Amira, gave her the necklace and plant fake memories so that she would steal the God's key and come to this location (Helheim) and take the Demon's Key to unseal Bahamut. Amira doesn't believe them and wants to see her mother to remove the God's key from her body. Martinet produces Nicole from a block of ice, and Nicole is a shell of former self and screaming in pain, and the demons reveal that they had used Nicole's essence to construct Amira. Amira goes to hug Nicole to see if a miracle to happen. Nicole does stop screaming and says Amira's name before fading away, and Amira screams in anguish. Amira is then raised in the air and given the Demon's Key to complete the key to Bahamut, and Belzebuth then seals her in a ball.
Your mom being alive is a lie.
On the road somewhere, Rita is in Bacchus' carriage asking Bacchus if he knew any demons who could turn humans into demons (like how Jeanne turned into a demon). Bacchus is about to give the answer but they hit a bit bump on the road. The bump turns out to by Azazel, who is injured badly but not dead. Bacchus and Rita capture Azazel and Rita asks Azazel to spill the beans on everything he knows, and Azazel is willing to do it if Rita is able to bring him to Ebos (the demon city?). Bacchus and Rita see the flash in the distance created by the joining of the God and Demon keys.
Favaro getting some tongue.
Back in Helheim, Favaro gets free by saying he wants to join the demons. After being released by Belzebuth, Favaro tries to attack, but Martinet sees through the ploy and tongue-feed Favaro the demon-transformation drink. Favaro is then turned into a demon.
This is the episode where everything goes wrong. As foreshadowed by Amira's visions, her journey to seek out her mother was all part of Martinet and Belzebuth's plan to unseal Bahamut. Amira was built for stealing the God's key and bringing it back to Belzebuth, and her mother Nicole was captures and barely alive. Amira gets turned into the final key, and on top of that both Jeanne and Favaro gets turned into demons. I was thinking Favaro might do something with that Bahamut spine that he is carrying, but he ended up doing no such thing. I also thought Bacchus would do something about Jeanne being burned at the stakes and being fed demon liquid, but he ended up doing nothing. Of course, that's probably not too surprising since the gods and angels don't like to intervene in anything unless they are threatened (as Favaro did to Bacchus). The whole crisis has evolved to this point mostly because the angels decide to let the humans keep watch on Amira while providing no supervision or assistance whatsoever, and Martinet pretty much does whatever the hell he wants and gets Jeanne wronged, put on execution and then turned into a demon.
Things are looking dire for the good guys at this point. The only person who is doing something useful is Rita, and maybe Favaro, Amira and Kaisar will have to count on her and Azazel to save their behinds. Of course, Favaro might get himself out of trouble even if he is now a full demon. There's probably no point counting on Kaisar to save the day lol. As for Azazel's return, Azazel probably wants to return to the demon city to rat Belzebuth out to Lucifer, and that might help. We still haven't learned why exactly Belzebuth wants to free Bahamut. Probably Belzebuth wants to use Bahamut's power to rule the world, but will the demon be able to control the beast?