This is Y/N and his partner archie the archeops who was given to him by his mother Olivia.
His z ring.
And his rockium he received from his mother after her grand trial.
He has a keystone on a necklace that replaces the z crystal that he has in the image above
This Z ring used to be his deceased father's.After his death Y/N was different. He never interacted with any of the children and was very distant.
Only his mother and pokemon could talk to him. But they really want him to make friends which is why he is going to the pokemon school.
Y/N can also understand the minds of rock type pokemon and with this skill he also befriended and captured regirock who he keeps in a pokeball on his neck.
He only uses regirock for major issues or to protect his family(This isn't Brandon's regirock)