I need a DARKNESS system. I think it might be kinda hard to pull this one off. And I'm using RMXP with Pokemon ESSENTIALS.
It works in the way that when your walking through the map or battling your Pokemon start building up on this factor DARKNESS. When it reaches a certain degree it will make them weaker at about 50% their actual power. This can't be healed at a Pokemon Center and the Pokemon must be left at a POkemon Rehab Center where, depending from Pokemon to Pokemon, will be there recuperating (for example a pidgey might take 2 hours to be ok but an Onyx might take 1 full day and some might take longer). Also there are these items called REHAB MEDICINE. There are 3. The first heals 70% of the DARKNESS factor the second heals 85% and the last heals them fully.
One more thing it's supposed to be an affliction like POISON. When the Pokemon hits the margin in which it is afflicted by DARKNESS (which also varies from Poke to Poke. Some species are unaffected and you might even find some that aren't affected even though their species is) there should appear a grey icon saying DRK.
I know this might be too much but I think it's a challenge right?
Hope we can get to work together. I'm not in any rush. Take your time...