Highlander: The Search for Vengeance

Wikipedia: "Highlander: The Search for Vengeance is an animated spin-off of the cult franchise Highlander. It was directed by Yoshiaki Kawajiri (Ninja Scroll, Vampire Hunter D: Bloodlust) and was written by David Abramowitz, also the writer for Highlander: The Series, Highlander: The Raven and Highlander: The Source. The film was a joint venture between Imagi Animation Studios and Madhouse Studio, with Imagi providing the script and the soundtrack, while Madhouse produced the animation."

Synopsis: "Colin MacLeod became Immortal after his first death in 125 AD in Roman Britain, when his village was attacked by the conquering Romans. Immortal Marcus Octavius was leading the Roman Empire's military forces in hopes of creating his long-dreamt-of utopian society. Octavius killed Colin's wife, but was not able to kill Colin himself, as his body had landed within Stonehenge on holy ground.

Waking days later within Stonehenge, Colin is left confused about who and what he is, and how he is not dead. It is at this moment that the spirit of a former druid of this holy site, Amergan, begins communicating with MacLeod, and explains to him what he is. Colin learns of The Game from Amergan, and the druid becomes his life-long teacher and conscience.

The movie interlaces flashback scenes of this and Colin's following plight for vengeance throughout time, as Marcus attempts to re-enact his utopian society through force and fear. Colin finds Octavius in a post-apocalyptic future New York City, where he is busy making plans to release a deadly virus. After a final duel, Colin defeats Octavius, and his Quickening destroys the virus in question."