Rough Roman Memes

Explanation: Of the 26 Emperors during the Crisis of the Third Century (it depends on how you count them), only 3 died of natural causes. 2 were of plague, which was a major contributor to the crisis. 1 (Carus) was literally struck by lightning while in his tent, giving him two places on this chart.

For bonus points, the 6 Emperors before the Crisis (Geta, Caracalla, Macrinus and his son, Elagabalus, and Alexander Severus) were all assassinated as well. An eventful century!