Challenger

Here the ‘one’ is a pronoun

• A pronoun is a word that is used instead of a noun or noun phrase.
•  Pronouns refer to either a noun that has already been mentioned or to a noun that does not need to be named specifically.
• Common pronouns are he, she, you, me, I, we, us, this, them, that. 
• A pronoun can act as a subject, direct object, indirect object, object of the preposition, and more and takes the place of any person, place, animal or thing.