A review by sherwoodreads
The Sundered Realms by Casey Blair

This is a quick, fun read for readers who like romantasy. The world building is fun, and I absolutely loved the fact that the magic could be done by writing math as spells. (Or, that's how I envisioned it, anyway). Two very bright research nerds find one another and negotiate their relationship while battling demons and some determined wizards, in an intriguing world setup.