I just realised when watched again the first prolog from DRV3. Seems when The Monokumarz introduced themself to the others, Kaede seems pretty shocked and say something liked "You're Monokumarz? Then that means--" before being interruped by one of the Monokumarz. What could this mean?
That’s something a lot of other people have wondered! There
are so many things about the prologue that really do stand out on another
Not only do Kaede and the others seem definitely familiar with the Monokumerz, but there’s also the matter of Miu’s line about talent at Amami (“Why’re you talkin’ like someone who’s got talent!?”) and Amami’s line to the Monokumerz where he asks “Why are you doing this ridiculous copycat routine—” before they interrupt him as well.