Well I have a theory, on star allies its says that the butterfly will come on the judgement day n afterlife stuff, so if we take a look, the butterfly always appears whenever something bad is aboud to happend (or in a positive way, another of kirby's adventure is about to start) what this could mean is that the butterfly always makes its appereance in kirby's world whenever *it* knows a powerfull being will appear meaning that it will have another vessel (galacta knight and fecto forgo) for it to emerge in its true form (beliving that morpho knight its the original appereance of the butterfly since its hinted that it didn't necessarily copied its appereance from galacta as we can see it looks the same after absorbing forgo) Its worth mentioning that apparently, it obligatory needs beings with massive power for them to be their vessels, as we can see it has only possesed two entities very known to have a destructive power, this could mean that the butterfly has such a enormous power that it can only be resisted by very few.

Now heres the other deal, the butterfly has tried to interact with kirby in various occasions before, as we can see in the start of return to dreamland it lands on him the same way it did with galacta knight, but it apparently isn't able to posses him like that so this leads me to two things: kirby is equally or far more powerfull than the butterfly, so it doesn't have the power to control kirby OR as we can see the butterfly also is with the tittle of dream eater, so it means the butterfly maybe uses as vessels entities that should no longer be there/aren't supossed to be there?? idk this is only just and extra point to where I want to go. The thing is, the butterfly has been the only enemy that represents a danger to kirby, we can se kirby is powerfull enough to defeat its own original being (void) but the butterfly is meant to represent death and afterlife so unless kirby is just too freaking OP to kill the death, I think the butterfly will become a very interesting and frearsome enemy