Board Thread:Questions and Answers/@comment-25216437-20161028194226/@comment-26131865-20161028194855

1. You don't "have to", but it's pretty much mandatory if you want to clear some tough stages.

2. Use tanky units like Titan Cat and Whale Cat that can bear some hits from Master A. I also hated Master A until I got the uber Super Galaxy Cosmo that outranges him...

3. Go to the Stories of Legend, there should be an event subchapter called "Autumn = Sports Day!". You have a chance to unlock him each time you beat a stage (you have more chance to unlock him with harder stages, so keep beating the last stage you can).