Markov Device

The Markov Device is a device that was created by Dr. Brion Markov which has the power to cause an earthquake. Developed by Unidac Industries, it was later revealed by Malcolm Merlyn, moments before he supposedly died, that there were two of these devices made. Malcolm explains that "if there is one thing he learned in business, it would be repetition." Malcolm planned to "level the glades" with this device, and as we find out in later episode, he does. After it was activated on the day that Malcolm "supposedly" died, it destroyed many buildings. As a result, 503 people were killed, including, Oliver's closest, and best friend.

Appearances
Season 1 Season 2

Trivia

 * The name 'Markov' and the fact that this device creates earthquakes is a clear allusion to DC character Geo-Force and his sister, Terra, as their real names are Bryan and Tara Markov.