There is no one in the street at night.

There is nobody in the street at night.

The third person is often used in narratives.

The first person is important in French grammar.

The second person is very important in this conversation.

She is a grownup now.

I want to meet him in person.

She is the queen of dance incarnate.

A legal person is a legal entity distinct from its members.

A natural person can be a citizen or a resident.