>>50826101Exodia isn't even real in it's own game. It's just a card. It appears only digitally after its card is played in the game. It does not exist outside of the game within yugioh.
In stark contrast, giratina exists in the pokemon world as a real entity.
No matter how you try and blend these worlds, they would never meet or be close on power levels. It's like asking, non-hypothetically, if giratina could defeat something in our world. It doesn't make sense.