Here we have a battle between two legendaries who have been corrupted in some way:
Primal Dialga: turned primal due to the collapsing of Temporal Tower and the destruction of Time itself
Shadow Lugia: Basically turned into a shadow pokemon by Cipher to be the first "impossible to purify" shadow pokemon
Who is the most powerful according to what we see in games and anime?
Who was harder to beat?
Who had the best theme?
When purified or recruited, did you give it a nickname after the pokemon is back to normal?
How often did you use this pokemon