Who is Amelia on Chicago Fire? Brett's family explained

The wedding between Sylvie Brett (Kara Killmer) and Matt Casey (Jesse Spencer) was a star-studded event. Kelly Severide (Taylor Kinney) came back from Arizona, and fans know how tricky it is to get him to stay in one place these days.

All the usual suspects were there, but one Chicago Fire character who may have caught fans off guard was Amelia (Everly Rapp Petlak). You'd be forgiven for not remembering who she is, given that she doesn't have an established last name, and has only appeared in one other episode.

Amelia is Sylvie Brett's half-sister

She does, however, play a big role in the Brettsey story. Amelia is Brett's half-sister, which is quite the complicated saga for those who forgot. Brett had a complicated relationship with her biological mom, Julie (Kelly Deadmon), stemming from the fact that Brett was put up for adoption at an early age.

They managed to rebuild their relationship in season 8, around the same time Julie was pregnant with her second daughter, but she died as a result of birthing complications. Brett was traumatized upon finding this out, and her half-sister, Amelia, was taken in by her dad, Scott (Jeff Diebold).

Brett stayed in touch with Amelia over the years, and her lone appearance to date was in the season 10 episode "Fog of War", when Casey took the half-sisters to Shedd Aquarium. This small visit was a big moment for Brett, in retrospect, as she explained to Casey at their wedding.

Amelia previously appeared in season 10

It was during this season 10 trip that Brett realized Casey would make a good father, and decided that she wanted to spend the rest of her life with him. Things got complicated by Casey's decision to move to Oregon, of course, but Brett eventually made good on her gut feeling.

Amelia doesn't have a lot to do at the wedding, but her presence was definitely felt by Brett and Casey. The couple are embarking on the next chapter of their lives, with adopted children to look after in Oregon, and Amelia was the first child in which they looked after together.

A small detail in the grand scheme of things, but the sort of detail that makes Chicago Fire such an emotionally satisfying show to watch.