Raikou is not in Pokemon Diamond. Are you using an action replay or a game card that may have been altered? Did you mean raikou (4 legs) or raichu(evolution of pikachu)? How did it appear?
Not really that rare... in Pokemon Diamond you can find Sunkerns on Route 204
You can find it in Crater anywhere on the map(s), but it's really hard to find.
i really do not know
Get it really drunk.
Any Pokemon can be a Shiny. It is just really rare.
There is actually nothing you do with Entei, Raikou, and Suicune (Being a legendary dog-catcher myself,). Just the pleasure (Not really) of having the three.
all the Pokemon on route 210 in Pokemon diamond and pearl are ponyta, geodude and if your really lucky you can find onix.
It maes the Pokemon holding it slower. Pointless really!
It doesn't really make sense!
no that is a glitch such as mew3-6
starly and shinx their evos are really great....
um, it is all your opinion, but a lot of people will say arceus because he is supposed to be a god pokemon. He isn't all that great (in my opinion) Raiko has some very good moves and stats, so i really can't tell you who is better, sorry