Just some quick jargon you may need to understand throughout the books.
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Thanatos - Greek derived word meaning death. Thanatos is the Office Zane represents.

Mortis- Latin derived word meaning death. Mortis is Thanatos's pale steed/ Limousine/Boat etc.

Chronos - Greek derived word meaning time. Chronos is the Office Norton represents.

Clotho - Greek (once again) the youngest (and preferably,) most beautiful aspect of fate with high sex appeal. Spins the threads of life. After her first husbands death, Niobe accepts the Office of Clotho.

Lachesis (Lak-i-sis) - Greek. The middle aged aspect of fate. Measures the length of life. After her second husbands death, Niobe steps up to become the incarnation of Lachesis, the first person to ever be an incarnation twice.

Atropos (Ah-trop-us) - Greek. The oldest aspect of fate. Grandmotherly Cuts the threads of life. Orlene offers her best friend (Tinka)'s father the Office of Atropos.

Mars - Greek. The incarnation of war. A person with high respect for war, knowing how to use it effectively also has had training in all kinds of defence and fighting. Mym settles for the Office of war to keep himself from marrying another.

Gaea - Greek. Incarnation of Nature. Can control everything to do with nature, flora, fauna etc (even the needs of humans e.g needing to go to the toilet.) After successfully completing her quest to find the Llano, Orb herself steps up to the Office called Gaea. Ge is her nickname.

 Purgatory - The place of indecision. When a soul isnt fit for heaven or hell because they're in balance exactly, they go to purgatory to sort out their souls.