It is the Pelipper that takes the job of sending mail to the player’s rescue team base. It sent two letter to the player, one when the player is about to escape from Pokémon Square, and another when the player returns, titled as ‘A mail from Pelipper’.
Letter when the player is about to escape from Pokémon Square
It’s a farewell, but only for now.
Until the day I can deliver mail to you again…
I’ll always be waiting.
-The wandering postal carrier,
A Mail from Pelipper
‘Yo! Amigo! It’s awesome you’re back!
I’ll be delivering mail to you again!
I’ve been looking forward to this with
my bill outstretched!
I’ll deliever tons of mail, so you’d better
be ready! Amigo!
-The wandering postal carrier, Pelipper-‘