New Castle County Police say they were called to a home on McMichaels Turnpike on Sunday evening.
Police say a victim reported that her older sister and male cousin had entered the house and that her cousin, Thomas Lovell, grabbed a butcher knife from the kitchen and threatened to kill her and another sister.
Police say the victim's older sister, Elizabeth Robson, then allegedly argued with her two sisters and was repeatedly told to leave. Police say Robson attacked her sisters, causing injuries to their faces.
Lovell has been charged with burglary, possession of a deadly weapon during the commission of a felony and other charges.
Robson was charged with burglary, assault and conspiracy.