> b-but it doesn't state they share the same one as Rockruff.
Bitch, why else would they wait until Rockruff's reveal to mention their secret. It could have been stated when they were first revealed, but they waited for Rockruff specifically.

The new day and night mechanism in both games plays a big role, and it's not gonna be just so your pupper can evolve into a different doggo. It's for the starters you ungrateful pieces of shit.