- He is known for his confidence in his terrible singing voice. He regularly subjects the neighborhood children to horrendous singing recitals, which is sometimes combined with his equally bad homemade dinner.

- He also frequently steals other children's toys and books under the pretext of "borrowing" them, unless the toy is damaged. This is how most fans considered Gian to be a major antagonist mostly to Nobita and his friends.

- Although he bullies the other children (mostly Nobita), he is terrified of his mother, who runs the local grocery store. He founded his own baseball team named after himself. Although Nobita is often blamed for the losses against the baseball team's rival, the "Tyranos", Gian and Suneo still force Nobita to play because they do not have enough players.

- Gian has a younger sister named Jaiko, whom he adores.

- However, he does not hesitate to help them, including Nobita when they are in real trouble, which often occurs in the movies.

[Source Amended from Wikipedia]