My thoughts are in blue, words to delete are in red, suggested rephrasing is in orange.

Ursula is born a witch under the loving tutelage of her Grandmother Altagracia, who is a powerful witch of haske, the magic of good light. Altagracia fiercely battles to keep the girl out of inuwa, the evil magic of darkness, as addictive and destructive as heroin, but under the pernicious influence of Altagracia’s wicked twin sister, Ursula falls—and then rises to become the most powerful and wicked witch in the region, terrorizing its people with unspeakable atrocities. Good set up, but I guess my only question is, what's the goal for Ursula here? Is she a ruler? How does she benefit from using her powers for ill?

When Ursula hears of a prophecy that the daughter of her mortal great-niece, Gabriela, will grow to be the witch who destroys her, Ursula vows to murder all of Gabriela’s daughters as soon as they’re born. Altagracia, once Ursula’s most powerful ally, now becomes her greatest enemy. She is old and weak in the face of Ursula’s unprecedented power, but she is smarter and determined to protect Gabriela’s baby girls, fulfill the prophecy, and rid the region of Ursula’s malignant presence. This is all perfectly fine and reads well, but it's very generic - there's a bad witch, a good witch, a prophecy, and a goal to eliminate the one who will unseat the ruler. That story has been told a million times. What makes yours different?

“The Witches of Ziohoza” is a 97,600-word dark speculative fantasy with elements of horror. It is set in Colombia, South America from 1889 to 1937 this could be what makes it different. This needs to be in the body of the query itself, not buried down here. Incorporate the setting into the query. Right now it reads like high fantasy set in a different world, not like something set in relatively recent history in our own world and narrated entirely by the good and bad women who populate it. It’s a traditional witch story with cats, potions, enchanted cottages, night-dark humor, and the thunder and sparks of hurled spells designed to disembowel. At the end is a surprise twist as tricky as the witches. A query isn't the place to tease. The body of this promises nothing new, and while the setting does draw interest, the plot has to have more than just the generic setup, and a promise of a twist that isn't shared with the agent

I am an American writer, playwright, editor, and copywriter with a BA in English who has, for twenty years, lived in Colombia, not far from where this story is set and where, to this day, witchcraft haunts its people. Great bio Readers who like Alex Grecian’s Red Rabbit, Neil Gaiman’s Ocean at the End of the Lane, and Alexis Henderson’s The Year of the Witching will enjoy this story, as well as those who like their wicked witches particularly nasty. There's nothing here that really tells us that these witches are particulary nasty. If that's the case, show us, don't tell us. Also, considering recent events, you might want to take out Gaiman as a comp.