Chapter 487 - 486: Wow, What an Appetite!
The hatching of Larvitar was known only to Cain and his Pokémon.
For now, Cain had no plans to reveal Larvitar's existence to anyone else.
Even though he wasn't weak anymore and had gained a certain status in the League that made owning a Larvitar plausible, there's a saying: "The tallest tree in the forest is the first to be cut down."
Just like when Professor Oak decided to keep Cain's discovery of Slowking's evolution method a secret.
Cain had great talent as a breeder, and if he also displayed exceptional skill as a trainer, many groups might feel threatened.
To most people, Cain's decision to build a gym seemed like nothing more than a youthful whim. After all, he was still young, and opening a gym for "fun" didn't seem like an issue.
But if others learned of Cain's high potential as a trainer as well, some might not take it lightly.
Not everyone was as tolerant as Giovanni.
Larvitar had not yet been placed in a Poké Ball. Since he was just born, it wasn't suitable to put him in one yet as it might affect his development.
However, since Larvitar's first sight upon hatching was Cain, there was no concern that he wouldn't recognize his trainer.
Cain just had to wait until Larvitar moved past his newborn stage to keep him in a Poké Ball.