Marshall Bowen was an hotel owner who lived in San Francisco. He was also an Watcher. During his life he observed four Immortals

Duncan MacLeod - 1853 to 1856.

Elijah Denton - 1857 to 1869.

Catherine Becket - 1869 to 1878.

Kit O'Brady - 1879 to 1888.

In 1888 he died.