Sorry to disappoint but Darkrai isn't the "satan" Pokemon. Giratina is.. Why?
Lets take a look.
How many horns does Giratina have on its wings? 6.
How many legs does Giratina have? 6.
Around its neck, The "rib cage" How many "ribs" does it have? 6. I believe that would be the number of the beast.
In its origin form you can also see that Giratina has horns down its tail, And how many? 6.
Just thought id clear something up for you.
Sincerely, Pokemon nerd.