Lore: incest (lore)

Any type of sexual act or romance between individuals who are genetically related (family), such as brother and sister, uncle and niece, or father and daughter. This does not include adopted children or people who are only relatives-in-law. For those kind of scenarios, pseudo incest applies instead.

For the sake of tagging and blacklists, this is also to be applied to posts with characters who are genetically related in official media/canon, even if the artist hasn't made a statement on the matter one way or another. However, if the artist does state that the characters aren't related, their interpretation overrides canon.