Infiltrator!

Once during an ordinary meeting with a clan of ninjas, it has been noticed that more ninjas have turned up than usual. The ninjas realized that these might be ninjas’ enemies - the pirates. Each person, dressed as a ninja at the meeting, said a few words. The cunning ninjas lied about their fellow ninjas in order to keep their secret and told the truth about the pirates. The pirates tried to unmask them, lying about the pirates and telling the truth about the ninjas. From the following statements, can you identify the ninjas?

Ninja A: Ninja B is a ninja

Ninja B: Ninja C belongs to Ninja A's group

Ninja C: Ninja C doesn't belong to Ninja F's group

Ninja D: Ninja A belongs to Ninja B's group

Ninja E: Ninja B belongs to Ninja C's group

Ninja F: Ninja E belongs to Ninja A's group

Remember that, ninjas and pirates will lie about individual ninjas or pirates, not about groups of ninjas or pirates.