A conqueror takes over a place by using military force. If you enjoy role-playing video games, you might like taking on the persona of a conqueror who battles evil orcs in order to rule their territory.
Generally, conqueror is used to mean the winner of a war or the leader of a vanquishing army. You can also use it in a figurative way for someone who wins or defeats others in a game or sport: "My conqueror in the chess match was that tiny ten-year-old kid." The Latin root of both conqueror and conquer is conquirere, "to win or procure by effort."