Stephen Miller and Stephen Bannon.

Here's some info on Miller:

https://www.splcenter.org/hatewatch/2019/11/12/stephen-mille...

https://www.npr.org/2019/11/26/783047584/leaked-emails-fuel-...

https://www.nbcnews.com/news/latino/white-supremacy-was-behi...

And on Bannon:

https://www.vanityfair.com/news/2017/09/steve-bannon-has-a-n...

https://observer.com/2019/05/steve-bannon-afd-party-germany/

Bannon wasn't there for the whole presidency, but he still did damage. Miller is the reason why child separation became a thing.