I need to create a virus for a fan fiction i want to write

Hello, and thank you for your time who ever takes a second to read this. As I am stuck on a cool virus idea, I want to write a fan fiction. I have the main villain for it, Dr. Hana von Rosenberg, daughter of a Japanese branch scientist and a old royal family of German i have mostly everything even a little help to get a virus for it will be greatly appreciated thank u again for listening