Normally, my Silversix (Elemental/Piercing) shows grey numbers on the standard pink jelly cubes (reduced damage, strong to piercing)- which is why I stick to my Master Blaster. However, I have noticed that it pops larger, blue numbers against the mini-Royal Jelly cubes, which suggests that the minis are somehow neutral to elemental and piercing. Even odder, in the southeast room of Royal Carpet Runaround where you see the little green jelly cubes, my Silversix does even more damage to them than the mini-Royals (by a factor of ~2x), but still pops the 'normal' blue numbers.
I haven't checked with shadow, but this seems to suggest mini-Royals have neutral resistances, and the mini-greens are the same but with lower overall defense. This doesn't really affect gameplay much, but I like poking at the mechanics. Anyone have more input here?
I'm not sure it's neutral resistances. It's odd, with my Avenger and my Faust the second swing on mini-Royals/purples always shows up as Gold stars/numbers, but the first is always blue. The green mini's definitely have reduced defenses though.