- Pedro of Castile won the nickname of 'the Cruel'. Many deaths and persecutions are attributed to him in his desire to take revenge on Leonor de Guzmán, his father's long-standing mistress, and her family. Nevertheless, as one of his main sources is Pedro López de Ayala, the chronicler of his rival brother who became Enrique II of Castile after defeating and killing Pedro at Montiel, it is possible that the bloodthirsty character of Pedro may have been somewhat exaggerated for political purposes.
- Fernão Lopes used Pedro López de Ayala's chronicles quite extensively, therefore he may have inherited that bias. Nevertheless, it may be interesting to keep count of the deaths that Fernão Lopes attributes to Pedro of Castile in his Crónica de D. Pedro, or Chronicle of King Pedro of Portugal.
- Other deaths en masse beyond the individuals named below: all the inhabitants of Cariñena when he took the town in 1364. [Pedro, ch. 34: 28-29]
- The crews of five Aragonese galleys, except the oar makers because he needed their services (1364). [Pedro, ch. 35: 52-57]
- Pedro of Castile did not come to the aid of the town of Murviedro, which was being besieged by Pedro IV of Aragon, because he did not want to face a pitched battle, unable to trust his own men. He had caused so many deaths that he was not sure of the loyalty of his own army (1364). When the people of Murviedro surrendered to the King of Aragon, they decided to join the cause of Enrique of Trastámara, rather than returning to King Pedro, fearing death at his hands. [Pedro, ch. 35: 69-76]
Chronicle entries in which Deaths attributed to Pedro King of Castile appears: