The bully would torment the younger kids.

To cause severe physical or mental suffering to someone.
The loud noises would torment the dog.
She felt tormented by her worries.
He would torment himself with regret.
torment someone
be tormented by
torment and suffering
torture
afflict
anguish
The pain was a constant torment for her.

Severe physical or mental suffering.
His memories of the accident were a source of torment.
The constant noise became a torment to her concentration.
She felt the torment of loneliness every night.
emotional torment
physical torment
live in torment
suffering
anguish
distress