you have to send mail to your friends in the games freuquently

You can obtain the Onion Knight job anytime after the Wind Crystal. Getting
the Onion Knight Job is a very easy task, but leveling it to its FULL potential? That's a
whole different story! Now, to get the Job:


First, trade Friend Codes with a friend.
message board.
Second, if you have already, send 7 messages to your friend.

REMINDER: You only have to send 7 letters TOTAL to complete all of the Wi-Fi
sidequests. Receiving letters does nothing! Once you send 7 letters, you'll NEVER have to
connect to Wi-Fi again!
Third, send a bunch of letters to Topapa until he sends you a letter talking about how the
children have gone missing and they can't be found anywhere!
Fourth, Go talk to Topapa, in Ur Village, to learn more.
Fifth, Head on over to Altar Cave and go in.
Deep inside the cave are the lost children. When you finally meet up with them,
it looks like they're in some big trouble that they might need a little help with!
Sixth, defeat the Bombs and watch the scene. For your efforts, you will obtain a Crystal
Shard. This shard contains the Onion Knight Job which you can now use!