Tamsin

Tamsin is a valkyrie who becomes Dyson’s partner in season 3 of Lost Girl. This partnership between a dark fey (Tamsin) and a light fey (Dyson) is supposed to be an experiment in creating a more enduring peace between the two sides. 

She is attracted to Dyson from early on and is not happy that he is chasing after Bo. 

As time goes on, she becomes attracted to and eventually falls in love with Bo. This complicates her life significantly as she is supposed to be hunting Bo down for a nebulous, but probably evil, entity.