Nekoko is one of the Orochi Necks of the anime Kannazuki no Miko.
Nekoko's personality is the same on the other anime cat girls: joyful, comical, tantrum maker (wants everything when she wishes) and a bit jerky. But, she is a bad girl too, and gets angry with Souma and his betrayal.
Nekoko suffered various medical experiments (probably during the war) like an animal and after this, he goes serves Orochi and like the medical experiments, uses syringes with beneficial or harmful substances for whom she ejects them.
Nekoko is the third Orochi neck that attacks the priestess (she attacks after heals Girochi), and she is defeated by Souma.
After, like Girochi, she attacks again with help of Corona and Reiko, but the three are defeated.
When Girochi become stone, she goes avenge on Chikane, but with the same make of Souma (that's before defeated Nekoko two times), Chikane defeats Nekoko and petrifies her. With Chikane's sacrifice, Nekoko became a happy and normal human.