The first thing she did was to replace all his ministers with her own, and one of those new ministers was her slave, a Shiite Muslim woman Fatima.
Fatima was a Tajik or Persian woman who was enslaved some time between 1216 and 1221 and was later acquired by Töregene. Eventually they became friends - or more.
I first read this story in a book called The Secret History of the Mongol Queens by Jack Weatherford, which I highly recommend. He writes: “[Fatima] enjoyed constant access to Toregene’s tent.”
It's hard to say whether their bond was romantic or just platonic, but as I was reading about them I couldn't help but think it was more than just friendship, and that line didn't help change my mind.
After making her a minister, Töregene made sure Fatima got even more power at court, none of which was normal for women at the time and it made a lot of powerful people very unhappy.
I wish I knew more about them, sadly, as it is, all I know is the ending of their story, which is brutal and one of those that shows the extent of human cruelty. Töregene's son, the new Khan, who was really only in power because Töregene made sure he would be, still felt like Fatima was in his way and demanded his mother turn her over to him to be killed. She refused and threatened to kill herself if he hurt Fatima but... he got her anyway. Töregene herself died a year and a half later.
The reason this story is so sparse is because most stories about Mongol women were ripped out of "The Secret History of Mongols" and those that survive are often attached to the male stories. So the only reason we know this story is because Töregene's son hated Fatima so much that she became relevant to his own story.
I wish I could link to online sources about them but aside from wikipedia the best source is probably the book I mentioned - also a great and well written source for a whole lot of Mongol queens history - and a book I haven't read but seems to be Google's favorite - The Tiger Queens by Stephanie Thornton, which seems to be somewhat fictionalized.