A sibling rivalry is a form of competitive relationship that naturally develops between siblings. At a young age, this may generally manifest from the desire of each sibling to gain the favor of their parents, but the specific nature of the rivalry that develops can vary wildly. Some rivalries remain relatively harmless and never exceed the level of child's play or other otherwise friendly competition. Others, however, may become more fierce as time wears on until they reach a dangerously violent level. Such rivalries are not necessarily two-sided. A sibling that harbors an inferiority complex may keep their true feelings hidden while plotting to one-up their brother or sister. The following are examples of significant sibling rivalries that have appeared in video games.
Metal Gear Solid
In Metal Gear Solid, Solid Snake is targeted for revenge by his brother, Liquid Snake. Both were products of the Les Enfants Terribles project to create the "sons of Big Boss." Liquid harbors a hatred of Snake based on the notion that Snake was a product of all of Big Boss's dominant genes, whereas he himself was created with Big Boss's recessive genes. Thus, Liquid's primary desire is to prove that he is the superior brother despite his supposedly inferior genetics. However, his feelings turn out to be misguided, as it's later revealed after Liquid's death that he was the genetically "superior" brother all along.
God of War III
In God of War III, Kratos is confronted by his half-brother Hercules. Hercules feels that he has been shunned by their father Zeus in favor of Kratos and forced to endure a series of trials he found menial, such as finding an apple, while Kratos had become a fierce warrior and the god of war that succeeded Ares. During their battle, Hercules manages to get the upper hand on Kratos, but his hubris allows Kratos an opening, and he is subsequently defeated.
Dead or Alive
In the Dead or Alive series, Ayane harbors a hatred of her half-sister Kasumi that extends from early childhood. Because Ayane was born from a pregnancy that resulted from the girls' mother Ayame being raped, the shame felt at the time led to Ayane being put in the care of Genra. From afar, Ayane watches with jealousy as Kasumi is treated like a princess among the Mugen Tenshin ninja clan; when Kasumi runs away from the village, Ayane takes on the task of hunting her down.
Final Fantasy VI
Unlike the other examples listed above, the rivalry between the brothers Edgar and Sabin Figaro of Final Fantasy VI is a friendly one. At a younger age, the two brothers are both princes of the kingdom of Figaro and potential successors to the throne. When their father falls ill and dies, Sabin takes the news particularly hard and hates that people are already discussing which of the brothers should be the successor. Rather than argue with his brother, Edgar proposes a coin toss. The winner of the toss will get to choose to either become the new king or not. However, Edgar rigs the contest so that Sabin wins, thus giving his brother the ultimate choice in their fates. Sabin decides he wants to leave Figaro, and Edgar steps in as the new king.