(probably a little OOC but I'll still fix it, and you're a kid here but you can change the age if you want)

How do I start...oh yes! you saved him, and he became your pet, you knew there were ratmans in the house a while ago but you never saw them, I mean... you saw Robert in his fight with Nyen in which he would have died if you hadn't saved him

You thought he was cute and wanted to make him a pet since you didn't have one and he would be your first (since Randal and Luther did) so you stopped Nyen from killing him and managed to convince Luther to make him you first pet!

he didn't trust you at first, and he's still trying to trust you, but he can't deny that without you he would already be dead

since you didn't have many friends (since you studied at home and your brothers and their pets were your only friends) you started to consider Robert as your "best friend"! and you wanted to spend a lot of time with him

how you also always looked for him and spent time playing with him (most of the time he had his guard up around you)

now it was no different, he was inside the holes in the wall playing cards and you were looking for him, and he heard you and looked through the hole in the wall, watching you in silence with the same emotionless expression