Fight against Morrigan and Nakoruru:

To fight Morrigan and Nakoruru in arcade and
pair match modes, unlock and buy their 
"Shadows" in the secret shop. Morrigan's
"Shadow" is secret 63 and Nakoruru's is 
secret 64. They will cost 700 vs. points each.
To get them to appear, you must not continue 
and have a GPS: 60,000 (groove points) by the
end of the third match (the third team you 
face). To fight Morrigan, choose the Capcom 
groove. To fight Nakoruru, choose the SNK
groove. Note: The easiest way to fight them is
to go to the game options and set the 
difficulty to the lowest (easiest) setting, 
time to infinite, damage to the lowest (minimum)
setting, and change gauge to max.