User blog comment:Plasmaster/Tracer Joins in the Blink of an Eye!/@comment-25275196-20160915044803/@comment-25275196-20160919010727

I was thinking a similar function to [my Fafnir Knight moveset], where you can transform with Down Special. In game, HDD can be activated by using up 20% of your total SP, or in the most recent game, using up one block of your EXE bar. So maybe you could have an SP bar that fills up with regular attacks, and decreases over time when HDD is active. Still, you should decide how to make it work yourself, since you're making the moveset, after all.