Politeness: Most Polite
Suffix: -sama
Examples: The villains call Beryl, Queen Beryl-sama. Sailor Moon calls Tuxedo Mask Tuxedo Kamen-sama.

Politeness: Professionals
Suffix: -sensei
Examples: Used for teachers, doctors, or anyone who is an expert or leaders in their field. Miss Haruna, the schoolteacher, is called Haruna-sensei or just Sensei.

Politeness: Normal Politeness
Suffix: -san
Examples: Used for everyone else.

Politeness: Senior Students
Suffix: -senpai
Examples: Title for an older schoolmate. It implies someone you look up to or whose examples you follow. Although it’s a formal term, it’s also used amongst friends. Sometimes used by girls even to address their own boyfriends if that boyfriend in an upper grade. Makoto (Lita) calls her “old boyfriend” senpai.

Politeness: Less formal
Suffix: -kun
Examples: Used between friends or to address someone more junior than yourself. Mostly used for males, but also used by bosses to address junior employees of either gender.

Politeness: Least formal
Suffix: -chan
Examples: Talking to best friends or to relatives. In Sailor Moon, the girls call each other Usagi-chan, Mako-chan, Ami-chan, etc.

Politeness: Pet names
Suffix: -chan
Examples: Usagi calls Mamoru Mamo-chan. -chan can be used for anything cute like children, babies, pet animals, or girls who are younger than yourself

Politeness: Pet names
Suffix: -ko
Examples: Mamoru calls Usagi Usako (-lo is a feminine ending). Not using any suffix indicate a close relationship which could include immediately family, childhood friends, or adult lovers. Sensei and Senpai can be used by themselves or as a suffix added to someone’s name.