MEET the worst people in the world: Nov. 28, 2011 edition. They are Cesar 'Big Man' Ruiz, 34, and his girlfriend Crystal Valdez, 28. Valdez and co. were getting ready to celebrate the fourth birthday of her son Christopher on Friday in Chicago. On Sunday, the twisted pair were charged with first-degree murder, concealment of a homicide and child endangerment. Christopher was beaten to death at the family home, his body discovered by his grandparents who had arrived with birthday cake and presents for his birthday bash. He died from multiple blunt force injuries 