Is the "take control of a character" a passive that occurs before the when revealed of the new plot cards?

If I take control of a character which has a character agenda and it gets killed, does it end up in my opponents dead pile or become his character agenda

Is the "take control of a character" a passive that occurs before the when revealed of the new plot cards?

Like all Castle plots, the passive "take control" effect that happens when this plot is sent to the used pile comes AFTER any "when revealed" effect on the plots that were just revealed. Rule of thumb - Castle plot effects happen in the same passive step as Golden Tooth Mines.

Note that when a new plot is revealed, the duration of Taken Captive ends immediately . (It is not a separate passive effect; it is the end of a duration.) So in the following round, the owner regains control of the captured card BEFORE any "when revealed" plots.

If I take control of a character which has a character agenda and it gets killed, does it end up in my opponents dead pile or become his character agenda

There are a bunch of other threads on what happens to character agendas when they die under an opponent's control. The short answer is that if neither the controller or the owner has an agenda, it becomes the owner's agenda. In all other cases, it goes to the owner's dead pile.