I remember someone here in forums completed his Itachi Susano'o from participating in that event (From last december's Christmas Events) .. He's Michefragt, not sure if i spelled it right but as far as i remember, this is event is good to complete your Itachi Susano'o .. My leader calculated it and it will cost you around 500cps per frag .. Search for the thread titled "Itachi Susano" and the author should be Michefragt, you may find what exactly he said there ..