Familicide, or the killing of one's own family members, especially your spouse, progeny, or parents, has always been viewed poorly in most societies, though in some cases there were exceptions.
For instance, in Ancient Greece and Rome the practice of leaving a newborn child to die of exposure if they were born physically deformed was considered perfectly acceptable. It has also served as a method of gaining greater power via getting rid of competition, or for conserving resources in extreme cases during hard times (if the bodies didn't also end up becoming the resources).
- A Deadly Affair: When an extramarital affair results in one of the parties involved (usually an enraged spouse) killing the others.
- Genocide from the Inside: Killing off your entire society, which would include your family by default.
- Grandfather Paradox: Killing one's ancestor via time travel, which may end up unmaking the murderer in the process (unless they replace their own ancestor in the family tree).
- Honor-Related Abuse: When it turns into honor-killing, killing someone for perceived "dishonor" of their family.
- Inheritance Murder: Murdering family members to obtain their inheritance, or murdering the proprietor of an estate to gain wealth.
- Princeling Rivalry: Killing off competitors to a royal throne.
- Kinslaying Is a Special Kind of Evil: When killing one's relative is considered a Moral Event Horizon.
- Offing the Offspring: Murdering one's own children.
- Pater Familicide: The murder or murder-suicide of an entire immediate family unit, generally by the father, due to an inability to deal with personal failure.
- Self-Made Orphan: Killing both of your parents or your sole living parent.
- Sibling Murder: Someone kills their own brother or sister.
- Til Murder Do Us Part: The killing of your spouse.