This video is an animation of 500 Million, But Not A Single One More, by @jai
When I was getting feedback on the storyboard from Jai, he mentioned that there is an actual god of Smallpox: Sopona. We decided to use it to lightly inspire our design by adding a mask similar to the ones found in wooden statues representing the god.
Apparently, in Nigeria there were cults of Sopona that strongly opposed vaccination. At the bottom-left paragraph at this link, there's an interesting story. Dr. O. Sapara, a Nigerian physician, infiltrated "the sopono cult", described as a large secret society in western Nigeria that used to cause smallpox outbreaks to generate clients to "cure" and to follow-up on blackmails. Sapara infiltrated the society and helped the government ban the cult as an illegal organization. After the cult was banned worship of the God continued.
Jai rightly mentioned the priests of the cult as a striking example of the most hollow humans allying with the enemy.