Ryusaki is an alias he used when he was working with the police to capture Kira, it's not his real name (why would he tell the police to use Ryusaki so Kira couldn't find his name if it was his real name?)
Until it's been made official by the creators of death note I'm not going to believe what some random person who had only just joined the forums says. I find it silly that everyone believed them as well without asking for proof, anyone could just join and make up a name and say its real that way. |