Guinan

Guinan was a mysterious time sensitive native to a parallel universe. She worked as a bartender in Ten Forward on the USS Enterprise-D in the 24th century.

Biography
In 2366, she began receiving memories of things that she felt she should not actually remember. When the Eleventh Doctor arrived on the Enterprise and experienced the same problem in 2368, Captain Jean-Luc Picard brought him to Ten Forward to meet Guinan. They had a familiarity with each other that they shouldn't otherwise have. These memories were due to their abilities to sense disturbances in time, and they realised that the Cybermen had somehow altered history in order to bring their respective universes together and forge an alliance with the the Borg. (COMIC: Assimilation²)