Through normal gameplay you can't but I'll tell you some ways to get a legitimate Lugia.In third generation,if you have the Mystic Ticket,(which you can't get anymore,except through cheating) you can capture it at Naval Rock,then you can migrate it to Pokemon Diamond through the Pal Park.You can also get one by trading with Pokemon XD Gale of Darkness.Purify Shadow Lugia by getting all of the "chambers" in the purification chamber to be a "best circle",then trade it to a third generation game,and migrate it to Pokemon Diamond.Lastly,you can capture one in Pokemon SoulSilver,through normal gameplay,or Pokemon HeartGold in the post-game storyline and trade it over to Pokemon Diamond.
These are the real ways to get a Lugia in Pokemon Diamond.
to get suicune on Pokemon diamond without action replay is to migrate from Pokemon fire red version or leaf green
no you have to get is from an action replay or go to a Pokemon event
Missingno is not avalible in Pokemon Diamond without help of the Action Replay.
There is a way to do it without cheating. Just simply trade a Pokemon that knows fly. Example: you have a staravia in Pokemon pearl that knows fly. Just trade it to Pokemon diamond.
action replay
I don't think that there is such thing but maybe with an action replay.
There is no other possible way of getting suicune without migrating or action replay its a legendary anyway and you just get them for show
Action replay
No
no you have to get is from an action replay or go to a Pokemon event
Not Possable
It is Impossible without an action replay
You can't without an action replay.
Missingno is not avalible in Pokemon Diamond without help of the Action Replay.
What moves do you want it to know (any) and what LV. do you want it to be? Nicknames?
In Diamond & Pearl? Impossible without migrating, trading, or Action Replaying.
you trade it or use action replay
Pokemon modefier from action replay.