In my story a time traveler goes back in time to kill Hitler... the story then revolves around him living the past out without Hitler. In my very limited knowledge of WWII, it seems like it still would have happened but not at that scale.
Was there a commander/general/second-in-command that would've taken the helm and went ahead with the Holocaust?
Weeeeell, the holocaust is not one simple thing that came out of nothing. It was not something that Adolf one decided one day over coffee with the guys.
What you have to keep in mind is that Jews, gypsies, tattare, homosexuals, and all the other groups murdered in the camps were universally reviled. Not just by the Nazis. Not just in Germany. All over europe, less in some areas, most in the east.
Google the concept of POGROM and GHETTO. For hundreds of years throughout the entire continent jews were forced to live in specific areas and subject to specific laws. And every once in a while crowds of upstanding decent citizens would descend on them to assault, lynch and plunder them.
This was not something that ended with the middle ages. My grandfather once remarked that the area in the city of Lund where my mother grew up, "Nöden", was the poorest district in town, where only travellers, jews and "Those honest people that could not afford better" lived.
Google EUGENICS and RACIAL HYGIENE. The holocaust was not motivated by hate, it was thought throughout Europe that weeding out the misfits would produce a stronger people. Jews were believed to be of an inferior race and should therefore not be allowed to procreate.
The idea of concentration camps was to separate men and women. and then use them as labor for the good of society.
Note that none if this started with the nazis, nor did it end with the nazis. Swedens forced sterilization program of "unfit" people didn't end until 1976. The US was the first to start a compulsory sterilization program in 1907 and it did not end until 1983, with the last actual sterilization in 1981.
If you wonder what that has to do with anything, the groups that were forcibly sterilized were homosexuals (ironically enough), roma, travellers, atheists, jews, "troublemakers", "promiscious persons", groups that were later systematically murdered.
[SIZE=-1]"Human heredity and Racial Hygiene" by Erwin Baur, Eugen Fischer, and Fritz Lenz was the name of a book that Hitler read in prison and which impressed him incredibly. I recommend that, and The SS-state by Eugen Kogon. [/SIZE]
The holocaust background is a convoluted and foul web of authoritarianism, fascism, pseudoscientific rationalization, racism and greed.