If the movie has a true villain, Dr. Eldon Tyrell is probably it. He's the mastermind behind the Tyrell Corporation, which manufactures the replicants and other artificial life forms, like owls and snakes. He expresses his ethos succinctly: "Commerce is our goal here at Tyrell. 'More human than human' is our motto." Basically, Tyrell is creating and enslaving super-humans in order to make money.
Yeah, he's not the most ethical businessman in the world.
We encounter Tyrell on two occasions. First, Deckard comes to see him at his penthouse—located at the top of a futuristic ziggurat or pyramid—where they discuss replicants, and where Tyrell introduces Deckard to Rachael. In line with his motto about commerce, Tyrell says that he considers Rachael to be nothing more than an experiment. Even though she's biologically the same as a human being, he views her and the other replicants as soulless tools. For instance, he's used memories from his niece to give Rachael a false sense of identity, toying with her very nature.
Slaves vs. Masters
Next, we see Tyrell when his creations come back to exact their revenge. Roy Batty comes to Tyrell's penthouse, and demands "more life" from the very man who created him. Tyrell says that he can't help—there's no way around the built-in time limit on the replicants' four-year lifespan. He offers Roy some pat consolations, telling him to delight in the time he has:
TYRELL:The light that burns twice as bright burns half as long, and you have burned so very very brightly, Roy. Look at you. You're the prodigal son. You're quite a prize!
ROY: I've done questionable things.
TYRELL: Also extraordinary things. Revel in your time!
ROY: Nothing the god of biomechanics wouldn't let you in heaven for.
After delivering this last line, Roy kills Tyrell, crushing his skull and gouging his eyes with his bare hands. It's poetic justice—the slave overthrowing his malevolent master.
Tyrell embodies the capitalistic or commercial worldview that has taken over in the futuristic world of this movie. Sure, we don't know exactly what the replicants actually are, but they sure as heck seem to be more than robots to anyone who takes a moment to interact with them. Tyrell doesn't see any "soul" in them because he thinking solely in terms of dollars. In fact, it's not much different from the way some people see wage-laborers these days.
The confrontation between Tyrell and Roy has some other implications, too. By creating life forms from scratch, Tyrell has basically been playing god, and when Roy approaches him asking why he can't have more life, it echoes a question a lot of people might like to ask God, or some kind of higher power. Why do we have to die? What's the point of that? Right? The replicants have to deal with the same kind of big questions we all do… only they have to ask to ask Tyrell.