Senghi Khan was an Immortal from Mongolia, born around the year A.D. 794. He and Khabul Khan met Kane in the year 1220, asking him to train them. Kane did, and together they pillaged villages all over Asia. In the year 1594, he followed Kane to Mount Niri in Japan, into the shrine-cave of his former mentor Nakano, who was training Connor MacLeod at the time. When Kane took Nakano's head, the resulting Quickening caused the entire mountain to collapse, with Senghi and the other Immortals trapped beneath for the next several centuries.
In 1994, after nearly 400 years of imprisonment, Kane and his henchmen escape the ruins of Mount Niri, due to the intervention of an archaeological expedition. Senghi wonders aloud where they are, but Kane says that it doesn't matter, as "[There] can be only one," abruptly beheading Senghi, and taking his Quickening.