It's rare now a days, that I read something new in a news article about ISIS that I already don't know of.
But here is an article with two new information:
1. ISIS fears Israel the most. And doesn't fear US or UK ground troops any bit.
2. They are ready to leave the Jews and Christians after accepting Zijya tax from them. But the fate of Shia Muslims is death. They are willing to kill as much Shia as needed. 150 million or 500 million, it's only a technical problem.
http://www.theblaze.com/stories/2015/12/28/reporter-who-spent-10-days-with-islamic-state-fighters-says-theres-only-one-country-the-jihadist-group-fears/