>>58555644
The game in Japanese Explicitly states that Regigigas reacts to the plates. No other pokemon does this, they are just guarding their own personal plates as they were the alpha pokemon elevated to guard them by arceus, its literally explained in the fucking campaign.

Regigigas is solely the only pokemon that requires other plates to interact with as he distinctly reacts and unseals in response to the plates, which are the corpses of the other giants.

No other pokemon has the explicit distinction that they are responding to your plates except Regigigas.