She is the voice of justice and she is one of Zeus‘ closest advisors. So close, that he even took her for a second wife (oh Zeus…). When she became pregnant with Zeus’ children, she gave birth to the Horae. These children represented the natural order of things: the seasons, the hours, but also the times of peace and war.
She also advises Hades, particularly when it comes to the judgment of souls when these pass into his realm. We guess this has something to do with her other children, which she conceived in a relationship with much older, darker force than Zeus: the primordial being Nyx. These children were the Morae. These are the three women that preside over the strings of destiny, spinning and cutting the lifelines when time requires them to do so.
Fun fact: Themis might be the most famous figure from Greek mythology. She is often depicted in courtrooms and other places of law and order. She is also known by the name of lady Justice.