I guess it is an inverse Spirit of sorts with Amadeus trying to be a mirror of Byodoin here. The decrease is powerfully, yeah, but if the ACE effect doesn't check the opponent's Speed, then maybe it's not as bad, right?. You also said that Dark Side did a similar effect to World of Ice, so that would likely be some sort of negation too. That gives us something like this:Kaoz said:Regarding Dark Side, I'm still not really sure. Going with Seakay's idea that it should be an inverse Spirit of sorts (or at least that's how I interpreted your suggestion), I almost feel like it would have to decrease the opponent's Speed instead of increasing Amadeus' own. The issue is that a -4 would be incredibly powerful, so I'm don't really know how to handle it yet.
Dark Side [Special - Lv 6 - 0.5 STA]:
Activation: Opponent's Serves/Specials with Lv <= 4 are negated.
Data: Opponent's Speed decreases by 4. At the end of the Data Step, Power increases by [???]
Extra: ACE if every opponent's Mental and (Power or Technique?) is less than ???. If ACE, then HP decreases by (the Power boost).
There's a few things to work out here. Negating Lv 4 abilities (Lv 5 with Draconic Descent too) seems about the right level, compared to what Volk, QP, Ryoga and other top players do. I'm not sure what the end step boost should trigger off of then this way, since it's not a Spirit move itself. I think Mental should still be checked for the ACE effect along with something else though. I guess that might tie into changing the ACE effects of Spirit moves themselves too from checking if Mental < 7. Maybe Dark Side could check the opposing stat(s)?