Rena Ryuuguu

One of the main heroines from the horror/suspense anime Higurashi no Naku Koro Ni which is based on a "sound novel" series of the same name. Gained popularity on /a/ and /c/ when she was revealed to be psychotic and murderous in Episode 2. Pics with Rena swinging a huge billhook became popular for a period of time, often with her signature quote "USO DA!!!" (That's a lie!!!). Also immortalized in a thread where her seeming attempts to break into the house of the protagonist with murderous intent was revealed to be nothing more than an attempt to deliver pizza. July 7th 2007 was what is known as Rena Day complete with Rena image floods. (Note: Her real name is Reina. 'Rei' is Japanese for zero and 'na' comes from 'nana' meaning seven.)