Dennis D. Siver is a retired Russian-born German mixed martial artist who competed in the welterweight, lightweight, and featherweight division of the Ultimate Fighting Championship.

Omsk is the administrative center and largest city of Omsk Oblast, Russia. It is situated in southwestern Siberia and has a population of over 1.1 million. Omsk is the third largest city in Siberia after Novosibirsk and Krasnoyarsk, and the twelfth-largest city in Russia. It is an important transport node, serving as a train station for the Trans-Siberian Railway and as a staging post for the Irtysh River.