i havern't really tried looking for him cause i'm in the fish city, but where is he? and what does he do exactly?

is he in the government district or is that somone else?

He's in the docks district of athkatla, there's a little map pin that says "cromwell's home".

They have the little info tidbits when you save games and load games and areas, and one tells you of Cromwell. They have the mapnote. They briefly considered calling the Docks District "Cromwell the Item Forger's District" but they nixed that idea.