Disclaimer: The boys belong to Minekura-sensei. I'm just taking them out for a spin.
Because That's How He Loves
Genjyo Sanzo
They think he doesn't know love, doesn't understand it. They are wrong.
The monks think he has reached enlightenment, that the only love he feels is the peaceful love that one should feel for all life, that signifies a lack of attachment to one and a respect for all. What a bunch of bull. Since when has Sanzo ever shown respect or concern for idiots, especially those he's never met.
Goku believes that Sanzo loves him because Sanzo heard him call and freed him from the mountain prison. Only a simpleton would believe that tracking down an annoyance amounted to love.
Gojyo thinks that on the slim chance that Sanzo is even capable of love, it's some strange, warped love. To Gojyo, love is touch—a friend's hand resting on a shoulder, a friendly wrestling match that leads to laughter, the feel of a woman's body pressed against bare flesh. But, Sanzo hates touch, avoids it whenever he can, and offers it rarely and hesitantly.
Of everyone Sanzo knows, Hakkai perhaps understands love best. Hakkai knows that love is pain and loss. Sanzo understands why Hakkai clawed out his own eye, how he could withstand the physical pain it caused. That's because Hakkai had already experienced the worst pain imaginable, the sight of the person you love most in the world bleeding, dying right before your eyes as you are helpless to stop it, helpless to keep that person with you. Sanzo knows that pain. Sanzo understands that pain.
Sanzo has known love longer and better than any of them. His earliest memories, back when he was still Kouryu, are of being loved by his father. Kouryu may have called him master, but deep down, Koumyou Sanzo was always father. They sat together in the fresh air, the comforting smell of pipe tobacco surrounding them, as Koumyou taught him the true meaning of enlightenment. Sometimes, Koumyou would recount the tale of hearing a voice in his mind and following that voice to the river where he found a baby. And, Koumyou would say he knew he was meant to rescue that baby, otherwise he would never have heard the child calling him. Whether it be a lesson on Buddism or the story of the child in the river's flow, Koumyou would often end the evening by ruffling Kouryu's hair.
Then, on the night when Koumyou bestowed on Kouryu yet more gifts, beyond those of the love and kindness he had already bestowed, the newly named Genjyo Sanzo watched as his mentor and father used his own body to shield his protege, watched as the man he loved and respected above all others was cut down and the sutra that belonged to Koumyou and had been bequeathed to him was stolen. As the blood flowed out of Koumyou's body and the breath left his lungs, Genjyo Sanzo felt his heart break into tiny pieces and a pain like he had never known before wrack his body and mind. Genjyo Sanzo decided in that moment that he would never love anyone again, never care at all about another living being, so he would never have to feel that pain again.
So it did not matter that Sanzo was forced to travel with Hakkai, Goku, and Gojyo. It did not matter that they shared a common goal or that he had saved each of their lives many times over. Sanzo did not love them, didn't even like them. But, Sanzo did know love, and that was why he would never love again.