Uh... Let's see. I'm going to pick this apart bit by bit. Please don't take anything I say the wrong way, I mean every word of it constructively, and I want to help you become a better RPer. Okay, so let's start with:
Severin Viper said:
Team Nightmare is a rising threat among the regions of the world. They are creating a pandemic of pain and suffering for the search of Darkrai, the Embodiment of Nightmares, in order to cover the world in horror and misery.
Darkrai doesn't really work like that. The Nightmare that anyone who gets near it descends into is completely against Darkrai's will. The nightmares are a defense mechanism that Darkrai can't control. That's why it isolates itself to New Moon Island. Based on that, no one on Nightmare would be able to even get close to Darkrai without descending into the Nightmare themselves.
Also, according to your previous post, Team Nightmare is a new gang operating out of the same region that Team Galactic works in. I don't really see how such a gang could become "a rising threat among the regions of the world", especially considering the point I made above on Darkrai.
Severin Viper said:
Team Nightmare is a group bent on enslaving humans and Pokemon alike with the power of Darkrai's Nightmares, and twisting the very fabric of sanity.
Darkrai's Nightmare doesn't work like that. As shown to us by the young man in Canalave City, you literally go into a coma as you descend into a Nightmare you can never wake up from without Cresselia's assistance.
Severin Viper said:
The head of Team Nightmare, who goes by the name is a man twisted by his own horrible memories from his childhood, and the encounter of Darkrai's uncontrollable power.
Without a Lunar Wing, or Cresselia, Nightmare Head SpaceBar would never wake up from this Nightmare Darkrai inflicted on him. Also, the bit on horrible memories reminds me on what Cyrus' grandfather said about Cyrus' parents. I'd try not to do too much to make a new syndicate boss too much like an old one, otherwise people are more likely to dismiss them.
Severin Viper said:
Team Nightmare specializes in Ghost and Dark type Pokemon, and are planning to create a machine that, once Darkrai is inside of, can spread fear across the globe.
A machine that can control Darkrai... Team Dim Sun, also know as Altru Incorporated, had one of those. After said machine broke, Darkrai basically sentenced him to death by locking him away in a Dark Void, though after the Legendary was calmed Darkrai released him. Though since Ranger are side games their place in canon is questionable at best. As with the previous statement on Syndicate Bosses, try to draw as few parallels to other syndicates as possible. Otherwise, again, said syndicate is likely to be dismissed.
Severin Viper said:
They steal Pokemon, then twist their anger and sanity to make them more blood thirsty.
This reminds me a lot of the Cipher Corporation, from the Orre games. Their Shadow Pokemon project locked away the pleasant emotions a Pokemon could feel, turning them into Shadow Pokemon, a being that had no qualms with attacking Pokemon and Trainer alike. Again, side game, so its place in canon is questionable, but it is another syndicate with major parallels.
As a whole, the take over the world plot, while tried and true, does get old. Especially since Cipher, Galactic, Plasma, and Dim Sun already tried it. For the most part, it isn't a very good idea to introduce more syndicates into the Pokemon world unless they have a region of their own. There tend to be too many conflicts with established canon.
As stated by Weeds, this whole thing feels more like a Fanfic then an RP. The fact that you focus on your own character, instead of sharing the spotlight, points this out quite a bit. Now, you said you've revised the plot, but I can't help but worry it'll appear in the actual RP anyway. Overall, I'd try and join a few RPs, see how we do things here. Learn from us, and then try to make an RP. Seriously, it's a lot easier when you're starting out to join other RPs then to throw your own ideas out and hope for the best.
Hope I helped a bit.