How Can I Get Mewtwo With Or Without Action Replay In Pokemon Diamond?

if you have a phone download pokebuilder. Then click on diamond. After that you search for mewtwo. When u click on it you can modify it [that means that you can give it any move you want]. After you modify it collect it from the GTS from your game. Hope this works.

You can't get it you have to migrate or get it fr your friend

Mewtwo is man made...

Run in grass hold r and you get mewtwo

Beat all the gym leaders and put a pika in your party pokemon. Put a moon stone on the pika. Go to your mini case that has gym badges in it. With your ds pen or finger scratch the gym badges. Then your pika will evolve into a mewtow

There is no way to get mewtwo without action replay
the action replay code is:94000130 fffb0000
d5000000 00000096
b21c4d28 00000000
b0000004 00000000
c0000000 0000000b
d7000000 00024620
dc000000 00000006
d2000000 00000000