Tā zài yóuxì lǐ dāng shàng le chéngbǎo de lǐngzhǔ.
He became the lord of the castle in the game.
Tips
usage
领主 specifically refers to lords who rule over a territory. For other types of 'lord,' Chinese uses different terms: 主人 (master/owner), 上帝 (God/the Lord), 君主 (monarch).