From the answers I've been given, it seems like this world encourages us to get stronger. Our "teams," at least.

[ Getting a clearer picture now. Kayneth's answer just helps confirm it. ]

Titans, monsters that vaguely resemble humans, who go out of their way to hunt humans. [ Her voice is dry and coming out as though she's reading from a textbook, histories lessons appearing in her head. ]

Over a hundred years ago in my world, they emerged, and placed humanity on the brink of extinction. Humans were only saved by hiding behind colossal walls. [ Pause. ] That doesn't seem to be the case in this world.