I just learned from Twitter that it's his birthday from Tomokazu Sugita.
Ah~ to tell you the truth, I greeted him in his account but he didn't respond. Of course they're too busy to reply so I am not expecting for that. As long as I've greeted them there's nothing to worry about but it would be nice if they've given at least a short thanks.
Anyway, Happy Birthday. w(^-^)w