Dusk Beyond the End of the World

The series follows Akira Himegami, a man who was put into cryogenic sleep. Prior to this, he confessed his feelings to his foster sister Towasa Omagi, a noted AI developer, before they were both shot in an assassination attempt. Waking up 200 years later on 2238, he discovers that the world has changed: an organization called OWEL is in power and trying to control all pre-apocalyptic technology. Akira is rescued from their soldiers by Yuugure, an android who proposes marriage to him, which he rejects. However, Akira believes that Towasa is still alive and aims to find her. He goes on a quest to find Towasa, with Yuugure joining him on his journey.

(Source: Wikipedia)