This story is being written for the Open Novella Contest IV on Wattpad in 2021. The prompts, modified slightly as the contest allows, are:

25. The war ended, and thus the Immortals returned to their natural state: forgotten, hiding in the shadows, until humankind is in need of them once more. They did not expect to be stumbled upon by a young [CIA-ish] agent.

6. The agent's usual job is to track down Immortals and infiltrate their groups, with the aim of gathering information and reporting them to the Agency. She's successful at her job until one day, she finds the Four Horseman of the Apocalypse and they change everything.

The cover image was created by Zied Gadri in 2020 and was taken from

https://www.zedge.net/wallpaper/6c3bd4a6-bb7c-418f-b073-462e5aa3df7e