- "You hear that, little boy? Your mama wants you dead."
- ―Cheese to Maelor Targaryen
After Lucerys Velaryon was killed by Aemond Targaryen, Lucerys's stepfather Daemon Targaryen hired two assassins, Blood and Cheese, to kill Aegon's and Helaena's children. Blood was a former "Gold Cloak" and Cheese was a rat-catcher who knew all the sewers around King's Landing and had worked within the Red Keep. This meant that they both had perfect recognition of the layout of the Red Keep. After breaking into the royal apartments, they found Helaena putting her children to bed. They demanded a son for a son. Helaena pleaded they kill her instead, but they refused. She named her younger son Maelor as the victim, and Cheese sadistically told Maelor that his mother wanted him dead. Some believe that Helaena named Maelor because Jaehaerys was heir to the Iron Throne, or because Maelor was just to young to understand. However, this request became an act of defiance against the Greens, as Blood just beheaded Jaehaerys with a single blow. By the time the guards came, the Queen was cradling her son's body. Jaehaerys's death would eventually led to his mother's insanity and suicide.
In the books
Once Prince Lucerys Velaryon was killed by Aemond Targaryen in the Dance Over Storm's End, Blood and the former Gold Cloak Blood were hired by Mysaria, Prince Daemon Targaryen's spymaster, to kill one of King Aegon II Targaryen's sons in retaliation. Through a secret passage, Cheese led Blood into the Dowager Queen Alicent Hightower's chambers in the Tower of the Hand. Cheese bound and gagged Alicent while Blood strangled her bedmaid. They ambushed Queen Helaena Targaryen and her children once they entered the tower and ordered her to choose which of her sons would die. She offered herself, but they refused and Blood threatened to rape her daughter Jaehaera Targaryen if she did not choose. She chose her younger son Maelor Targaryen, deeming him too young to understand the situation, and Blood instead decapitated her elder son Jaehaerys Targaryen. Blood and Cheese then departed, taking the prince's head with them.
Blood was captured and tortured to death, but Cheese was never found. Aegon II was furious and had all of the ratcatchers in King's Landing hanged. Ser Otto Hightower brought one hundreds cats into the Red Keep to replace them.