For me, the term 'rivalship' doesn't just mean two people competing for a title or goal. More often than not, they're on the same side. The term 'rivalship' goes well beyond simple rivalry--they compete on an internal level: strength, validation, acknowledgment, etc. Rivalships have more friction than not. They challenge each other mentally, morally, and sometimes even physically.
BUT! And this is important--they also share a unifying factor, be it duty or camaraderie or justice or a mutual (even if grudging) respect for each other. This is essential to the relationship and what sets it apart from being ProtagonistxAntagonist or just two people who hate each other. They straddle the line between love and hate, but ultimately fall on the love side. Sexual tension is also great, but it has to evolve past that--or start with something else and evolve into that lol. These are the couples that take a whole lot of effort to work, but are so very worth it in the end--and are that much stronger for it.
Rivalships have the potential to drive characterization and plot (to an extent, of course). Let's say that character X is angry and jaded. Character X meets character Z, someone who hopes and dreams despite a dark past and a darker future, and X thinks Z is a naive fool, but Z is just so optimistic that X grudgingly learns to hope again too. But maybe Z is secretly terrified because she has the weight of the world on her shoulders (or maybe just pressure from parents and peers) and, despite how exasperating X is, Z appreciates it--relies on it to keep her sane--when X treats her like just another human being. Rivalships bring out the best and worst in both sides. They frustrate the reader with constant external and internal conflict and, at least for me, pushes them to read on.
And, sometimes, seeing two characters who secretly like each other clash can be hilarious! =P
Disclaimer: This doesn't mean I don't like other sorts of relationships. When couples are romantic and sweet and just fit together--that's lovely to read as well (like Anna and Etienne from Anna and the French Kiss).
Rivalships that I can think of off the top of my head:
• Mr. Darcy and Elizabeth Bennett (Pride and Prejudice)
• Scarlett O'Hara and Rhett Butler (Gone With the Wind)
• Katniss Everdeen and Peeta Mellark (Hunger Games--literally rivals there)
• Val and Ravus (Valiant)
• Nick and Mae (Demon's Lexicon)
• Aislinn and Keenan (Wicked Lovely)
I leave you with one of my favorite rivalships of all time, Allen and Kanda from the manga D.Gray-man (who are not even canon and also happen to be both male):
Art by me :)
What rivalships can you think of? Which are your favorite? Or, if you're not a fan of rivalships, why not?