GLaDOS is a highly intelligent AI with no remorse, she does have a conscience, But she rarely uses it, instead she uses logic, And she talks strange

Wheatley is a dumb but humanish AI who has feelings and doesn't like being called a moron, as the counterpart of GLaDOS He uses emotions and a conscience.

Chell is the human test subject, And she doesn't speak a lot, she's chill

The turrets are childlike killing machines, and they're really sweet.

Space core: he literally just talks about space.