The latest Magic: The Gathering set Theros Beyond Death introduces a brand new god named Klothys, the God of Fate and Destiny in Theros. She is associated with red and green mana, and if you're wondering which part of the Gruul colors defines destiny, Magic head designer Mark Rosewater recently explained why.

"It's not that red/green philosophically cares about destiny," Rosewater wrote on his Blogatog. "Green cares about destiny. Klothys is red/green because she has red means to achieve a green goal."

The character design of Klothys is not typically what you expect in a Gruul card but Rosewater's explanation makes sense.
The story summary of Theros Beyond Death revealed what happened to Klothys:
Theros Beyond Death, the 83rd Magic: The Gathering expansion, is set to release on January 24, 2020.
Related: Ikoria: Lair of Behemoths Will Have A Story, Not Just A Summary