Question: is jaime lannister the kingslayer?
Answer: Jaime's twin is Cersei, the Queen of Westeros by virtue of her marriage to King Robert Baratheon. Perhaps the greatest swordsman in the kingdom, Jaime is derisively referred to as "the Kingslayer" because he killed the "Mad King" Aerys Targaryen in the coup that put Robert on the Iron Throne.