RE: Video Game EVs
Umm yeah thanks for the input DNA....anyway here's a more detailed perspective on EV Training that I'll explain. You'll want a Pokemon with a Nature that boosts a specific Stat by 10% like for example If it's ATK and Speed go with Adamant or Jolly Nature, then If you want to max out on your IV Value for a specific stat like for Base ATK go with a characteristic like "Proud of it's power" or "Likes to thrash about." Serebii.net has you covered on what IV Values get you the best results in EV Training.
http://www.serebii.net/games/characteristics.shtml
If you want the best results for EV Training, the Pokemon that your EV Training needs 10 Vitamins each on the 2 Stats it's going to max it's EV's on If you plan on going 252 EV's in 2 Stats like ATK and Speed for example for a Physical Sweeper set like Weavile. Then you need to give the Pokemon Pokerus and attach either a Macho Brace or a specific Power Item depending on which EV's you obtain first. For example, If you're EV Training in ATK first you want to battle against lots of Sawk and Bouffalant over by Opelucid City, they're located in the route to the Pokemon League in BW1.
Before you start EV Training though I would suggest stocking up on Hyper Potions and Revives as well as a strong Pokemon in your Party to help you gain experience along the way. So say you EV Train in ATK first, always send out the Pokemon you're trying to EV Train in your Party first, it faints then before you faint the opposing Pokemon use a Revive to heal the Pokemon your EV Training and knock it out with a strong Pokemon in your party. Keep doing this and count how many EV's your Pokemon gets on a notebook. If the Pokemon you KO give you 2 EV's per battle like 1 opposing Pokemon at a time then you should be able to get 252 EV's in one stat in just 20 battles.
Keep in mind that all Pokemon have Base Stats in the game that can benefit from EV Training so it's usually best to take advantage of their Base Stats to get really good results. Sometimes you don't really need to take advantage of a Pokemon's Base Stats on specific movesets but it does help quite a bit. I also want to point out that EV Training for a Hidden Power for a Special Sweeper can be a pain in the butt because you need a specific IV Value that gives you at least 70 Base Power for the Pokemon's Hidden Power that is meant to give you Type Coverage against Pokemon that the Pokemon your Ev Training is weak against. For Legendary Pokemon, Hidden Power shouldn't be that hard to take advantage of cause you won't need to worry about it's Base Power all that much but it could matter on that regard.
Breeding is also very important when it comes to EV Training, infact starting in HGSS up to now you can actually breed Pokemon with specific IV Values as long as the Pokemon in the Day Care has a Power Item attached that passes on that IV Value to the offspring as it's about a 50% chance just as it is for the Mother or Father to pass on it's Nature to the offspring when it has an Everstone attached in the Day Care which is still a 50% chance. So what I would do is have one Pokemon with an Everstone with the Nature you want and it's partner to have a Power Item attached with the IV Value you want just as long as they like eachother to increase your chances of getting an egg from the Day Care Man. That way when the egg hatches it has a 50%+ chance of getting both the Nature and IV Value you want. IV Value's are described in every Pokemon's Summary as a characteristic like for example, "Often dozes off" which is one of the highest IV Values for a Pokemon's HP stat.
The more the Pokemon your breeding in the Day Care like eachother the better your chances of getting more eggs to hatch, you also want to have a Pokemon in your party that has the ability Flame Body or Magma Armor like Magcargo so you can speed up the process of hatching eggs alot faster. Passing on Dream World Abilities through breeding on the other hand, it must be a female with an Everstone that passes it on to the offspring. Breeding DW Pokemon became alot easier in BW2 due to being able to pass on 2 Egg Moves to the offspring aside from the DW Ability as well. As always you cannot breed a DW Pokemon with Ditto to get an offspring with a Dream World Ability or as what some people call it, "Hidden Abilties". Egg Moves are important for getting a good moveset on a Pokemon but some of them can be taught via Move Tutor in BW2.
If you're going to EV Train for Legendaries, since you can't breed them you gotta catch them so what do you do? Well here's a trick I learned awhile back. Remember the ability Synchronize by Abra? It has a 50% chance of passing it's own Nature to ANY Wild Pokemon including Legendaries, so what you do is you have an Abra with Synchronize as the 1st Pokemon in your party with the Nature you want on the Legendary, use a Quick Ball or Master Ball to catch the Legendary and If it doesn't work then soft reset the game before you encounter the Legendary Pokemon until you get it right, it's worked for me so far. You'll also want to stock up on Revives for Abra so that you can get this trick to work, especially using a Pokemon with Yawn to put them to sleep to catch them easier. I usually soft reset the game until I get the right IV Value and Nature I want on the Legendary Pokemon I catch.
Just a word of advice, NEVER give the Pokemon your EV Training to hold an Exp. Share over a Power Item or Macho Brace because it won't earn the Exp. necessary to get the highest stats while also being infected with Pokerus. As for Pokerus, If it gets a smiley icon on it's Summary that just means it's not able to pass on Pokerus to other Pokemon in your party or Pokemon it comes in contact with in battle but it's stats will still double because of Pokerus though. If it becomes Midnight at the time you have a Pokemon with Active Pokerus then it will get the smiley icon so If you want to spread Pokerus to other Pokemon keep it in your PC Box. As for EV Training Lv. 100 Pokemon, it's very difficult to do in Gen V because regardless of how many Pokemon you KO your Exp. Bar never increases as a result cause the game registers the Pokemon as 0 to the next level.
If you want me to post links let me know...