The black AMAIM only goes by the name Ghost. It's a freaking monster, it's hard to believe that just an AI is controlling that thing, but it has no pilot.
It can override the special passwords that the 4 blocs have for their AMAIM parts and use them to repair itself. It's also what killed Gashin's father the one time he decided to let his son pilot his AMAIM while he was using a training one. It took a lot but, but the two of them managed to drive the thing off. But not before it wrecked their base camp and killed Risa, the young woman that Amou just met. The only thing that was left of her was her necklace... After that, Amou couldn't go on. He decided against joining Yatagarasu, but this time, they completely understood and respected his decision. You can't help but feel so bad for him, he was just a normal boy a few days ago and now someone he just met was killed during a battle.
After separating from them, Amou decides to go Risa's hometown to tell her family what what happened to her. But they all left due to the cruel treatment of the Oceanian bloc. For a single little thing, those people will take whole families and imprison them. And worse, the Deputy Governor who's in charge deals in human trafficking, so after the people are arrested, he'll sell them off.
The man and his daughter that introduced Amou to Risa's friends just had to cross paths with the Deputy Governor's car, which led to them getting caught. And the people in town didn't like that and left to protest, but the military just arrested them and went off to go arrest anyone connected with them. Risa's friend's told Amou to run, but despite what happened before, he went back to get Genbu and saved those people. After that he mets up with Gashin again and joins Yatagarasu. The episode ends with Risa's necklace on her family's grave.
While Amou and Gashin go to a nearby city to rest and get parts for their AMAIM's, the Ocenians smell the blood in the water and decide to launch an attack on the Asian military. Not caring about the innocent people that could get caught in the crossfire. And the two of them can't do anything because their AMAIM's aren't ready for fighting yet and they're too far away.
It's only when a yellow flying AMAIM arrives and fights off both sides that the fighting ends, it was so cool.