Walkthrough to beat the Elite 4 - Guide for Pokemon Diamond

To get you started on beating the Elite 4 you need to first have all the gym 
badges, get past victory road, buy at least 15 -20 revives and full restores 
and have your pokemon at Lv. 60 or higher. Anyway to get started the first 
Elite 4 member you're going to face uses bug type pokemon of the elite four 
members name is Aaron. Heres Aaron's pokemon team below and their attacks.

Elite 4 Member Aaron

Pokemon:                 Attacks:
Lv.53 Dustox             Double Team, Toxic, Bug Buzz, Light Screen
Lv.54 Heracross          Megahorn,Close Combat,Night Slash, Stone Edge 
Lv.53 Beautifly          Energy Ball,Psychic,Shadow Ball,Bug Buzz
Lv.54 Vespiquen          Defend Order,Heal Order, Attack Order,Power Gem
Lv.57 Drapion            X-Scissors,Cross Poison,Ice Fang,Aerial Ace

The 1st Pokemon Aaron will send out will be Dustox. By now you should be very 
familiar with battling Dustox through playing the game.Dustox likes to Poison 
you with Toxic so be careful because the damage increases. Dustox uses Double 
Team to raise its evasion plus it uses light screen to weaken your special 
based attacks.It knows Bug Buzz if your planning of killing this thing with a 
Psychic Pokemon. Your best bet would be to use any Fire, Rock, Psychic, and 
Flying type moves or Pokemon. Watch out for bug buzz if your using a psycic 
type mobe. The 2nd Pokemon he'll send out is Heracross another pokemon you 
should be familiar with fighting your rival.It has a really good array of 
attacks that can do some serious damage.Your best bet is to use your best 
flying,fire, and psychic type moves. If your using a fire or flying type 
pokemon watch out for stone edge which can do some serious damage and if your 
using a Psychic type pokemon watch out for megahorn. After Heracross he might 
send out Beautifly which you should be familiar with. It has an array of 
attacks at its disposal. If your using a rock type pokemon watch out for energy 
ball which can do some serious damage. Use your best rock,and fire type moves 
to knock it out. After Beautifly he might send out Vespiquen. Now this pokemon 
might take a while to knock out because of its high defensive and special 
defensive stats. It'll use defend order alot to raise both defense stats and 
it'll use heal order to get back to full health. The good thing about 
vespiquen is that it can't do much damage to u. Use your best rock type move to 
1 hit it since its x4 weak to rock move. The last pokemon he'll probably send 
out is his Drapion. It has an array of attacks that can annoy u. Drapion is a 
Dark and Poison Type so use you're best round type move to knock it out. And 
thats how u beat Aaron. Now proceed to the next room and heal your pokemon if 
nessisary.

In the next room you'll see the 2nd Elite 4 member Bertha who uses ground type 
pokemon. Your grass and water type pokemon might come in handy. Bertha sort of 
looks like Agatha from pokemon red,blue, yellow, fired and leafgree. Below is 
Bertha's team and their attacks.

Elite 4 memeber Bertha:

Pokemon:                      Attacks:
Lv. 55 Quagsire               Dig, Double Team, Protect,Sandstorm
Lv. 59 Hippowdon              Earthquake, Stone Edge, Crunch, Curse 
Lv. 56 Sudowoodu              Earthquake, Sucker Punch, Hammer Arm,Sandstorm
Lv. 56 Golem                  Brick Break, Earthquake, Gyro Ball, Sandstorm
Lv. 55 Whiscash               Fissure, Zen Headbutt,Rock Slide, Aqua Tail

Bertha's Quagsire will start things of. It likes using double team maing it 
harder to hit.Just relax and use your grass type moves to tear it apart.The 2nd 
pokemon she might send out is her Hippowdon. It started the battle with its 
sand stream ability so you lost 1/16 of your HP. Same thing as sandstorm which 
all of her pokemon know. Hit it with your best grass or water type pokemon. 
after Hipowdon comes Golem with extremely high defense. Hose it down with water 
or grass type move since its x4 weak to grass and water type. It also has high 
attack also. After Golem comes Sudowoodu with strong attacks and very weak to 
water and grass type moves. Lastly comes her Whiscash who has the same weakness 
as Quagsire.Use your best Grass type moves. It might take 2 hits to kill 
it.That's how u beat Bertha. Heal pokemon and proceed through the next door. 

Next up the third member of the elite 4 Flint who u saw in Sunnyshore City. He 
uses Fire type pokemon even though is team has other types due to the lack of 
fire type pokemon in sinnoh. Below is his team and their attacks.

Elite 4 member Flint:

Pokemon:                 Attacks:
Lv. 58 Rapidash          Solarbeam,Flare Blitz, Bounce, Sunny Day
Lv. 61 Infernape         Mach Punch, Thunderpunch, Earthquake, Flare Blitz
Lv. 57 Loppuny           Mirror Coat, Fire Punch, Sunny Day, Charm
Lv. 57 Steelix           Fire Fang, Rock Tomb, Screech, Sunny Day
Lv. 58 Drifblim          Ominous Wind, Will-o-Wisp, Double Team, Baton Pass

Rapidash starts things out since its very speedy, and pretty powerful. But with 
its low defensive stats just put it out of its misery with any water, ground, 
and rock moves. Next comes Infernape the monster of his team with very high 
attack and very fast. Use your best Water, ground, psychic, and flying type 
moves. Beware of ThunderPunch. After Infernape Comes his Lopunny. It has Mirror 
Coat so try taking it out with your best psychical based fighting type moves. 
Next come his Steelix the very slow but very defensive thing. Knock it out with 
your special based fighting, water, ground, and fire type moves. Last up the 
high HP and a bit annoyance Drifblim. Knock it out with yourbest ghost, dark, 
electric, ice and rock type moves. Heal up your pokemon and proceed to the next 
room.

After beating Flint the last elite 4 member Lucian who specializes in Psychic 
type.So use your best ghost, dark, and bug type moves. Below is his team and 
attacks listed.

Elite 4 member Lucian:

Pokemon:                       Attacks:
Lv. 58 Mr. Mime                Thunderbolt,Psychic, Light Screen, Reflect
Lv. 60 Medicham                Drain Punch,Fire Punch, Thunder Punch, Ice Punch
Lv. 60 Alakazam                Focus Blast, Psychic, Energy Ball, Recover
Lv. 63 Bronzong                Earthquake, Psychic, Gyro Ball, Calm Mind
Lv. 59 Girafarig               Psychic, Double Hit, Shadow Ball, Crunch

Lucian will start out with Mr. Mime with Light Screen and Reflect making your 
special attacks, and phtsical attacks weaker.It also has Psychicand Thunderbolt 
doing some damage.Use your ghost, bug, and dak types to put it out. Next up 
Medicham the powerhouse with fire, ice, and thunder punch and drain punch 
covering alot of the types. Use your best flying and ghost type moves quicky. 
After Medicham comes Alakazam with high special attack and speed. It knows 
focus blast a very powerful special based attack which can destroy your dark 
dark type. So wipe it out with your best bug and ghost type moves. Next up 
Bronzong the very defensive and special defensiveyetlow attack and special 
attack thing.It has levitate so ground move dont work.. Use your best Fire, and 
ghost type moves.Last up Girafarig who likes to throw Psychic around. It is a  
Normal/Psychic type moves. Dont use ghost type move insteaduse an bug or dark 
type move. That's how u beat Lucian. Heal up all your Pokemon and be ready to 
take on the champ.

Finally comes the Champion Cynthia the one who u encounted throughout the game. 
She has a variety of pokemon types so be ready for a tough battle. Below is her 
Pokemon team and their attackslisted.

Champion Cynthia: 

Pokemon                       Attacks:
Lv.61 Spiritomb               Dark Pulse,Silver Wind,Psychic, Embaargo
Lv.60 Gastrodon               Muddy Water,Earthquake,Sludge Bomb,Stone Edge
Lv.63 Milotic                 Surf,Mirror Coat, Ice Beam, Aqua Ring
Lv.63 Lucario                 Aura Sphere,Dark Pulse, Psychic, Earthquake
Lv.60 Roserade                Energy Ball, Shadow Ball,Sludge Bomb,Extrasensory
Lv.66 Garchomp                Dragon Rush,Brick Break, Earthquake, Giga Impact

Cynthia will start out with her Spiritomb with no weakness and high special 
defense and physical defense which means it'll take a few hits. Next up is her 
Gastrodon whose only weakness is grass so it might take 2 hits to take down.It 
has low defense, and high special defense. Next in her arsonal is Milotic areal 
pain to take down due to its high denensive stats.Take it down with your most 
powerful electric, and grass type move. It has high HP and takes time to take 
down. After Milotic is Garchomp the monster of he team with High attack even
though it has a x4 weakness to ice types. So tear Garchomp with your strongest 
Ice, and Dragon type moves. Next upcomes her Lucario with only ground, 
fighting, and fire type weakness. It has very powerful moves such as Psychic, 
Aura Sphere, and Earthhquake which does serious damage. Lastly comes her 
Roserade which shouldn'tbe threatening unlike the rest of her Pokemon. Hit it 
with your best fire, ice, Psychic, and flying type moves.It has High Special 
Defense and Special Attack. Beat Roserade and you've beaten the Champion. 

     Congragulations! You are the New Champion