Here is a link for Brave Frontier Japan 1.2.7 for iOS
Zippyshare.com - Brave Frontier JP 1.2.7.ipa
Now, I do not know if you need to be jailbroken and have appsync installed to install this file since it is a free game.
However, you can try changing the apple id of the game to your own. (Requires Winrar)
Step 1: Right-click Brave Frontier JP 1.2.7.ipa
Step 2: Open with and choose Winrar
Step 3: Double-click iTunesMetadata.plist (this will open the file)
Step 4: Change the apple id to your own and save