Enough of this fighting, before you get the board moderator, SPDShadowRanger, involved and you don't want that happening.
To settle the issue on Takuto, WE KNOW NOTHING ABOUT HIM! All we know he has a Darkrai, defeated all the trainers and Gym Leaders that faced him only using said Darkrai, and his looks matches said Darkrai.
Personally, I don't think he's evil, but he does want to prove he's the best so he got himself a Legendary and used it to slaughter anyone's Pokemon standing in his way. Now while he may not be evil, he can still be mean and be egotistical (and would you argue with a person who uses a Legendary as a common Pokemon, especially after he used it to defeat all your Pokemon single handedly?), but that just makes him a jerk and not evil (much like Paul). As for the way he dresses, well honestly he probably only looks that way to match his Darkrai. Would you be just as intimidated by his Darkrai if he wore bright colors, messy hair, and him having a cheery face?
As for Darkrai, we've only seen one evil Darkrai so far and that was in the Mystery Dungeon games. The other two Darkrai's we've seen in the anime was good (and "sacrificed" itself to stop the two other rampaging Legendary Pokemon really causing the problems, Dialga and Palkia) and the other just acted like any other wild Pokemon but just so happened to cause nightmares (though luckily a Cresselia lived nearby to chase it away). And I doubt an evil Darkrai would let a "inferior" human use it as a tool to battle.
As for why it was decided they needed a trainer with a Legendary, well honestly that's now probably the only thing which can now defeat Ash and knock him out of the tournament. As soon as Ash wins a Pokemon League it's intended that that's the end of his journey (though personally I would think he would keep on doing other competitions until he wins his home region's Pokemon League), so they need him to lose to go on to the next region. Let's go over the people who knocked Ash out of the leagues:
Kanto - Ritchie - Used almost the same Pokemon Ash uses.
Johto - Harrison - Used a Pokemon from the next Generation (Blaziken).
Hoenn - Tyson - His main Pokemon that was the one to defeat Ash's last Pokemon was a Meowth that dresses up like the fairytale character Puss in Boots.
Sinnoh - Takuto - Used a Legendary Pokemon (Darkrai).
Now out of those four, which one seems the most oddest? Tyson wins that category, but really being it'll become increasingly boring for Ash to lose against a trainer the same way he did in the last League they try to keep things interesting so this time they decided to use a Legendary. Oh, and as its been said several times, it's probably not going to be Darkrai that gives Ash's last Pokemon its blow, Ash will probably atleast defeat Darkrai but only have one Pokemon remaining for Takuto's Pokemon that helped him catch Darkrai to tear apart.
Edited on 08/15/2010 7:29pm