I don’t want to get too deeply into why Laoghaire returns to the plot, but Marsali does become important because she falls in love with a grown Fergus.
She’s the daughter of Laoghaire, who has had a slightly larger role in the TV series than in the books.
Marsali is a character who becomes important to the storyline after Claire returns to her own time and Jamie returns from prison.
The actress will be 18 when we meet her as part of the “Voyager” timeline.