>>57784231So you have no answer as to what it officially is. Therefore, my interpretation is valid until an official source adds context.
It's also an interpretation that has legitimate basis due to how Arceus in PLA is portrayed. When you complete your Pokedex and defeat Arceus in battle, it bestows upon you "a fraction of itself", a mere avatar, so it can experience being together with the trainer who fulfilled its grand design so brilliantly, without having to abandon its post as Literal God.
Thus, the same can be assumed of Giratina, one of the creation dragons, who lords over antimatter and the Distortion World, ensuring the balance of both worlds is kept intact by way of the normal world remaining logical, and the Distortion World remaining illogical. Something it couldn't really do if it was busy being chummy with a 10 year old kid.
Thus, BDSP having you fight a mysterious level 100 shadow Origin Forme Giratina implicates that this is the ACTUAL Giratina, and it wants you to prove your strength to be worthy of letting that avatar harness the power of its true form.
