I finally got pure majin status, thx to this guide >.<! Btw, the channel changing thing does work wonders. If you combine that will exterminating mobs and supers you will at least get 1 db drop every day or two. I got the last 3 today. Plus another db. I think it's a "false" dragon ball I guess. I'll insert a picture.
o.o really because i didnt see a single db mob for the past month now -_- or do i suppose go in dungeons looking for them?
Kill mobs in an area a few times. If that doesn't work change the channel. Kill, and if none appear change the channel. Also hunting in groups tends to work better but not always. Killing supers. Finding areas where db's are really bontiful.