Board Thread:Questions and Answers/@comment-33647649-20171222130452/@comment-32271305-20171222145520

You have to dokkan awaken SR STR Buffed Buu into SSR Sluggish Kid Buu, and then Z-awaken him to UR so that he'll have a 100% chance to raise the SA of any other Kid Buu.

Sluggish Kid Buu is actually a good card, so I decided to keep one copy, but Extreme STR is not a priority of mine, so I care more about raising INT Kid Buu's SA. Unfortunately I can only get him to SA5 at the moment, I'll have to wait until I summon more Buffed Buus before I can get him to SA10. Luckily SRs are a lot more common than SSRs, so it shouldn't take too long... hopefully.