Created by Arceus (i.e Pokémon god), Giratina is part of the creation trio, alongside Dialga and Palkia. Giratina was a lot more violent than Arceus expected, so it was banished to the Distortion ...

Pokémon Legends: Arceus is no exception here ... You'll need to beat Giratina in a fight initially before later being able to capture it. After collecting every plate and speaking with Cogita ...