BERLY is a character in OMORI.
OMORI first encounters BERLY in the PLAYGROUND playing tetherball with VAN. Apparently, BERLY threw the ball too hard and it broke off the rope, misplacing it. BERLY temporarily joins your party when you help him look for the ball.
As you search, you run into GRANDMA. BERLY notices she has the ball and takes it back from her. After you return BERLY to the PLAYGROUND, he and VAN will teach AUBREY how to headbutt and give her a BUTT CERTIFIKIT.