How do you get member card on Pokemon Diamond?

Answer 1

Enter any pokemart to see a man in green standing next to the counter. Talk to

him and he will give you the Members Card. Fly to Canalave city and head north

of the Pokemon center. There is a Harbor Inn that you can now enter. Once

inside, you will be put in a bed and taken to an island that just has Darkrai

waiting. Darkrai is level 40 and you cannot leave the island unless you

capture or defeat Darkrai so be sure to bring a party that can handle it.

NOTE: You cannot get into the Inn if you have not cured the sick boy with the

Lunar Wing. See the Cresselia section of the guide if you have not taken care

of the sick boy.