>>30125318Then my guess is that he had to leave his mother's abuse, and knowing that this Pokemon was suffering too, he had to take it with him.
After all, he needed something to defend himself with, so doing this not only saves Null but gives him a fighting partner (and eventually a friend). It's possible there might not have been enough time for him to get Lillie or something. He just had to get out of there and didn't think of much else. So left with not much else to do, he aims to get stronger, for the sake of his Pokemon and to either eventually save his sister or get revenge on his mother.
