The black-haired guy looking up scared in manga might have a paled complexion, dilated pupils, and perhaps a hand raised defensively. Different manga artists might depict it in various ways, but the core elements of fear would be present.
Often, such an expression might involve tense muscles, furrowed eyebrows, and a tremble in the character's stance. It all depends on the context and style of the manga.
He might have a curious or thoughtful expression. Maybe his eyes are wide and his brow slightly furrowed.
Maybe he had a bad day or got into a fight with someone.
The expression of a scared boy cartoon looking up typically includes a frightened gaze, maybe a hunched back, and hands grasping tightly. This indicates he's nervous about what he sees in the upward direction.
The scared guy on a roller coaster in a cartoon might have wide-open eyes, a scream on his face, and maybe even his hands grasping tightly to the safety bar.
They might be friends or have a romantic connection. It really depends on the context of the manga.
It could be Kurapika. He has black hair and is an important character in the manga.
One manga that fits this description could be 'Soul Eater'. It has various characters with different hair colors, including a blond guy and a black-haired one.
It could be that the guy has a thoughtful expression, maybe pondering the beauty or the mystery of the mountain. Or he might have a smile, indicating his enjoyment of the view.
The guy might have a concentrated look on his face, with his eyes fixed on the screen.
He could have a relaxed and peaceful expression, maybe enjoying the view. Or he might have a more intense gaze, as if he's thinking deeply about something in the sky.