Yes. Humans.

You're right of course. I misread it, and was thinking about humans, but even humans have changed the course of natural selection through modern medicine.

The Nazi's goal wasn't to breed a master race, they believe that there already was one (social Darwinism, which was popular at the time). The exterminations of people was done to make more lebensraum, "the territory that a state or nation believes is needed for its natural development, especially associated with Nazi Germany." They had run the numbers of their increasing population and their food production systems, primarily ag, and determined that they needed more land and didn't need the people current consuming the products of that land.

“Neither the current living space nor that achieved through the restoration of the borders of 1914 permits us to lead a life comparable to that of the American people.”

This is all based on Timothy Snyder's book "Black Earth"
[nytimes.com]

Agreed, but he took natural selection to the extreme, by ensuring that the breed stayed pure by selecting those that should breed together and removing any he saw as threatening this. Women with hereditary illnesses were sterilised and Himmler set up a program for pure bread women to bear blond haired blue eyed children to sustain the master race - hence my comment about selective breeding (as we do with dogs) as opposed to a random natural selection as mentioned in the original post.

It’s laughable you consider breeding programs natural.

Btw, to finish my initial thought, if your goal is to make a species into what you want it to be, refining it for a specific set of traits that you desire for whatever reason, clearly humans intervention into the process of selection of who's morphology (the form/structure of the biology, or the way gene's express themselves in the organism).

If your goal is for the species to evolve so that it is more competitive in its natural environment, then unless you know all the details of that enviro and can tailor your selection for it, then more than likely the selective pressures from its natural environment would produce the more best fitting results, although it would be slow, depending on the time it takes for an individual to grow from birth to reproductive age. Elephants are slow to evolve because they can't mate until about 10-12 years old. Bacterium's entire lifespan is about 12 hours, they swap genetic material via direct cell-to-cell contact probably within an hour. So in a year, you'll have about 700 generations of bacteria whereas you need about 12 years for a single generation of elephants. This difference matters because it is the recombination of genetics and occasional rare mutations that create the small differences in morphology that are selected, then those who reproduce pass their genetics onto the next gen. This is why fighting disease is so challenging (why there is a different flu shot every year [and influenza is all RNA instead of DNA, but that's a different conversation]).

Some much faster than others. Even the horseshoe crab didn't start out as such. It has stalled out for now, but it has at some point evolved, and its process is not done yet.