With a name like this, how could we not love this guy to death? El Capitan is the fourth and final character whose eyes through which we view the world, and we can't help but feel bad for him despite his elite status in the OSR. And yes: even though he is an officer for OSR, he's still a good guy.
Here's the tragic story of El Capitan: the Detonations went off while him and his brother (Helmud) were dirt-biking:
"The visual effect is that of a permanent piggyback ride." (18.8)
So he has his brother attached to his back, which is probably one of the worst fuses we have seen out of main characters. We feel even worse for him when we learn about his family:
The truth is he's always had to trust Helmud. For so long, they've only had each other. They never had a father, really, and when El Capitan was nine, their mother died of a virulent influenza in an asylum like the one he stands in front of now (18.12).
Ouch. His mother is dead and his father is non-existent in his life, so all he has is the company of Helmud. And really, Helmud doesn't talk much, and has very limited function. As we follow El Capitan around, we get the sense that he feels extremely lonesome… which might be a reason why he constantly risks his life to save the main characters in the later stages of the book. Ask yourself, if you were in his situation, what would you do? What would you think?
Sometimes, at night, while listening to his brother's deep breaths, he imagines rolling to his back—smothering his brother once and for all. If Helmud died, he would too, though. (18.14)
It ain't easy being El Capitan—whose name, by the way, is a nickname given to him by his mother when she put him in charge of the family. But there's a lot to admire in someone like him; even though his life seems bleak and lonely, he still carries on (with life, and Helmud).