Indefinite pronouns are pronouns that refers to one or more unspecified people, places or things. These pronouns are very useful in Japanese. First we will look at pronouns that end in ka (か). If these pronouns are used alone their meaning gets changed to a question.
Someone ate bread = dareka ga pan o tabemashita
Who? = dareka? (誰か？)
When these words are used with mo (も) their meaning changes depending on if the sentence is positive or negative. They can either include or exclude everything.
(I) always read newspaper = itsumo shinbun o yomu
The word itsumo almost always means always even when used with the negative. The word nanimo is not always preferred in every situation. There are different words that you can use in various sentences instead that mean the same thing.
(I) read it all = zenbu yomimashita (全部読みました)
(I) can't understand at all = zenzen wakarimasen (全然分かりません)
When you add the word demo (でも) the meaning changes to any.
Anything is ok = nan demo ii (何でもいい)