Fan Xian was the mastermind behind the assassination attempt.

The masterminds behind Fan Xian's assassination were Lin Gong, the Second Prince, and the Eldest Princess. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Second Prince assassinated Fan Xian because he did not want Fan Xian to take control of the palace treasury. The Eldest Princess might have wanted to kill Fan Xian to cut off the possibility of the Qing Emperor letting Fan Xian inherit the palace treasury.

The masterminds behind the assassination of Fan Xian were Lin Gong, the Eldest Princess, and the Second Prince. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Eldest Princess was the person in charge of the palace treasury. She might have hoped to kill Fan Xian to cut off the possibility of the Qing Emperor letting Fan Xian inherit the palace treasury. The Second Prince assassinated Fan Xian because he did not want Fan Xian to take charge of the palace treasury. The Eldest Princess wanted to help the Second Prince ascend the throne and needed to remove all obstacles.

The masterminds behind Fan Xian's assassination were Lin Gong, the Second Prince, and the Eldest Princess. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Second Prince assassinated Fan Xian because he did not want Fan Xian to take control of the palace treasury. The Eldest Princess might have wanted to kill Fan Xian to cut off the possibility of the Qing Emperor letting Fan Xian inherit the palace treasury.

The masterminds behind Fan Xian's assassination on Niulan Street were Lin Gong, the Second Prince, and the Eldest Princess. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Second Prince had assassinated Fan Xian because he did not want him to take control of the palace treasury. The Eldest Princess had done so to assist the Second Prince in ascending the throne. She needed to eliminate all threats.

The mastermind behind Fan Xian's assassination in Danzhou was controversial. Different documents mentioned different people, including Lin Gong, the Second Prince, the Eldest Princess, and Chen Pingping. However, there was no clear evidence to point out who the mastermind was. Therefore, according to the information provided, I am unable to determine who was behind Fan Xian's assassination in Danzhou.

The mastermind behind Fan Xian's assassination in Danzhou was Chen Pingping. Chen Pingping had secretly contacted Zhu Ge and passed on a secret order, causing Fan Xian to be assassinated in Danzhou. Teng Zijing was the person who carried out the assassination mission, but he was only a tool to be used. Thus, Chen Pingping was the mastermind behind the assassination of Fan Xian in Danzhou.

The masterminds behind the assassination of Fan Xian on Niulan Street were Lin Gong, the Second Prince, and the Eldest Princess.

The masterminds behind the assassination of Fan Xian in the Qing years were Lin Gong, the Second Prince, and the Eldest Princess. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Second Prince assassinated Fan Xian because he did not want Fan Xian to take charge of the palace treasury. The Eldest Princess wanted to help the Second Prince ascend the throne and needed to remove all obstacles.

The masterminds behind the assassination of Fan Xian on Niulan Street were Lin Gong, the Second Prince, and the Eldest Princess.

The masterminds behind the assassination of Fan Xian in the Qing years were Lin Gong, the Second Prince, and the Eldest Princess. Lin Gong obtained the token to control Cheng Jushu and smuggled him into the city. The Second Prince assassinated Fan Xian because he did not want Fan Xian to take charge of the palace treasury. The Eldest Princess wanted to help the Second Prince ascend the throne and needed to remove all obstacles.