An “evil” teenager has been found guilty of the savage murders of two sisters he stabbed to death in a north London park as they celebrated a birthday.Danyal Hussein, 19, repeatedly stabbed Bibaa Henry, 46, and Nicole Smallman, 27, after using his own blood to sign a pact with mythical King Lucifuge Rofocale, the Old Bailey heard.In a “campaign of vengeance” Hussein pledged to kill six women every six months to win a lottery jackpot of £321 million and carry on killing women as long as he was able, jurors heard.