Here is the source: https://www.tumblr.com/ask-crow-aus/759912849861754880/slytherin-assassin-lattemonstr-aishishiii . It is one reblog further down, as slytherin-assassin deactivated their blog and lattemonstr apparently has no post on their blog, probably deleted when they moved on to a different blog.

The Remaster Champion is in Player Core 2, which is listed as available on their website, but hasn’t been updated on Archive of Nethys. I don’t have the book myself, but according to a blogpost (https://paizo.com/community/blog/v5748dyo6uib0?Player-Core-2-Preview-The-Champion-Remastered) about it they said they still have causes, they are just not bound to alignment anymore.