Aka, "The unexpected consequences of transmigration". These are primarily stories wherein the MC is a victim of a transmigrator taking over their body (and generally messing up their life). Usually, the story starts with the MC...
Similar to reincarnation, transmigration is when the protagonist takes over the body of a person existing in (usually) another world. It is sometimes also used to refer to being transported back in time (in such cases where the...
In these manga/novels, the main character is transmigrated, reincarnated, summoned, or otherwise transported into the world of a book or novel. Common themes include trying to change their fate, manipulating the plot, and/or...
These manga fit the villainess trope (as outlined by our Villainess tag synopsis), except that the protagonist is male, not female.