i understand from a spoiler i read on a nother site that itachi killed his best friend or somthing in order to attain thelevel he is at now. i was wondering if you could tell me does th emanga actually say HOW this new level was attained? is it just by killing a person for no reason? doe sit have to be your best friend? whats the deal? is it an instantaneous transformation?

thanks, oh and try to keep the spolierage to a minimum please?