then train some more

ok ok I can help

1. Bring like 7 or 8 Reviver Seeds
2. Bring 2 or 3 Sleep Seeds
3. Bring 1 or 2 Quick Seeds
4. Have good moves that can go to atleast 2 or 3 tiles away.
Thats how I beat him twice! (second time u get 2 recruit him)

Listen to the pro who beat him in a few hits twice to Dialga , Palkia and Darkrai!

If you have an action Replay put this in, 94000130 feff0000 021acbao 00ffffff D2000000
oooooooo. BEAT any pokemon then press R. and wala your LV100. and to restore HP, 92372082
f7ff0800 121acb92 ooooo3e7 d2000000 00000000.press Y. And for Max HP,9237209c f7ff0800
121acb94 000003e7 d2000000 00000000.press Y. and trust me i did it a million times. And it
does not freeze or ruin your game in any way.

I beat him

I beat him by bringing all my reviver seeds, sleep seeds, and getting moves that can
paralyze him. Plus, if your partner can learn protect, you won't have to worry about him.

~A random pikachu

hes easy

i just let him attack my partner (pikachu) he got paralyzed and i just kept using combo
move on him. plus i use no seeds :P

ok easiest way (less items)(only on time)

you and your partner have to know dig first make dialga sleep or stun himthen use vile
seed on him (throw do not eat!) then take of all your partners moves except dig and put
exclusive move user on him/her make sure both of you can hit him with dig and if you and
your partner have really high sp. def. bring oran berries not reviver seeds.

if you need to recover

use stun seed on him and don't let your partner attack him (you don't attack either) then
use oran berries.