Article for Nishi
People have said that Seiya and Usagi should be together, and I don't blame them. After all, Usagi deserves the best, and SailorStarfighter is without doubt one of my favorite senshi. She is courageous, powerful, and beautiful; she has the voice of an angel and the heart of a warrior. Her loyalty to her Princess is unquestionable, and it's obvious that she's dedicated to her cause.
But she is not the one for Usagi.
For one thing, there's the matter of the long-distance relationship. Seiya lives very far away; if Usagi finds it hard to part with Mamoru when he goes to America, how would she feel when Seiya must return to Kinmoku Star? And don't tell me that Seiya will stay on Earth because of
her love. Seiya will never stay with Usagi. They are both loyal, dutiful senshi; Usagi will remain with the Moon, and Seiya will go back to Kinmokusei and serve her princess.
That's another point - Seiya already has a princess to protect and defend, and it's not Usagi. As a Kinmokusei senshi, Seiya must devote herself to protecting Kakyuu-hime, just as Mamoru and the senshi of our solar system devote their very lives to protect Usagi.
Mamoru, on the other hand, has no other calls on his loyalty. He has only one person he must protect: his Usako. He has sacrificed his life for hers several times before, throughout the centuries; he will not hesitate to do so again. At one point, he even cries out that Usagi is what keeps him alive. How can Seiya, a senshi with another princess and a duty far away, ever match that kind of loyalty?
And if you want to get technical, there is no match for a princess but a prince of equal rank. Mamoru-kun's Golden Crystal is the only perfect match for Usagi's powerful Silver Crystal. Seiya's Kinmokusei sailor crystal isn't even in the running.
Even Seiya realizes how impossible the match would be. In Act 46, as she watches Usagi walk away, she thinks to herself: "We are of different stations in the universe. This might be an unrequited love."