What is the ruling on intentional killing between a man and a woman?

The intentional killing of a soul, which Allah has forbidden except by right, is one of the gravest crimes and major sins. Its punishment is Hell, wrath, curse, and a tremendous torment, as if one had killed all of humanity. The obligation in intentional killing is retribution (qisas), whether the killer or the victim is male or female, unless the guardians of the victim's blood forgive freely, or for a bloodwit (diyah), in which case they may accept it in exchange for waiving the demand for retribution.