At another room in the Palace, Tyrrel enters having just overseen the murder of Edward Prince of Wales and the Duke of York, which he calls "the most arch deed of piteous massacre that ever yet this land was guilty of." His hit men were reluctant to murder such innocent children, but went through with it. Richard enters and is pleased to hear the princes have been killed. He promises to reward Tyrrel, who exits. Richard confides that he has imprisoned Edward Plantagenet, married off Margaret Plantagenet in a low marriage, killed King Edward's sons, and that Anne has died. Now he aims to beat Richmond to marrying King Edward's daughter.
Even the grizzliest assassins are appalled by Richard's tactics, but Richard remains unfazed by the blood on his hands, focused only on consolidating his power. By locking up and marrying off Clarence's children, Richard has deactivated any threat they might pose to him. Now all of his brothers' children (his contenders for the crown) are eliminated. Anne's death is, mysteriously, unexplained – it's unclear whether she died or whether Richard killed her. Both options seem plausible.
Ratcliffe enters and reports that the Bishop of Ely has fled to Richmond and that Buckingham, who also fled, is gathering Welsh forces to fight Richard. Richard pooh-poohs Buckingham, though he fears the threat of Ely. Declaring there's no time to lose, he orders Ratcliffe to start assembling men for battle. They exit.
Even as Richard manically consolidates his power, that power is quickly eroding – the Bishop of Ely and Buckingham were both loyal to Richard in the past but they have now turned against him as they, who were insiders, can more easily see that he wasn't just lying to his enemies—he was lying to his supposed "friends", too!