Why ``adversary'' and ``challenger'' and what are typical roles of those? I'm confused with words adversary and challenger, that are used in proof of security of some cryptosystems.
For example, adversary and challenger appear in the formal definitions of IND-CPA, IND-CCA, etc.

What are typical roles of adversary and challenger?

From my understanding, adversary refers to a player who tries to break the system while challenger refers to a player who provides something but does not try to break the system.

Are these correct?

Also, I'm wondering why challenger is not called as helper since it does not try to break the system. Rather, it is there to help the proof.
The word challenger seems like an attacker.
Suppose you are a member of a mailing list or of an anonymous cryptographic site. Now suppose there is some "new guy" who just joined and makes bold claims about having broken some cryptosystem. Now of course because you don't know anything about the "new guy" you don't believe them. Naturally they're really insistent, so you agree to challenge their claim that the cryptosystem is broken. This makes you, the skeptical person, the challenger.

Of course because the other is trying to break the cryptosystem they're the adversary against which the cryptosystem tries to hold up. Now of course you, the challenger, know that a total and complete break of any cryptosystem (e.g. ciphertext-only attack) is an unrealistic capture of the reality, so you agree to provide the adversary with some ressources, e.g. answering requests for encryptions.

So in a sense security games are protocols that allow adversaries to convince challengers that they broke a security property in the most reproducible and convincing way (e.g. because the adversary clearly at no point has access to the key).