Now let's talk about Sebastian for a second here. We barely know about his family, history, personality, or basically anything we need to know about his character. Even with not knowing this, his death made a big impact on the people watching the show (well, it did for me). He went down in a blaze of glory, sacrificing his life for Adiland's, her baby's and Meisner's safety. Instead of going to saftey with them, he stayed behind to fend off Viktor and the others. He was able to shoot down 3 of them, before he ran out of bullets. He needed one more, in order to kill Viktor. His luck was cut short. Though defeated, he still refuses to tell Viktor of Adalind's location. He knows that he will not make it out, even if he tells Viktor. Before the bullet went through his head, he remembered all the favors he did for Renard, and did the biggest favor for him in the end. He also remembered all he went through to do these favors. He was tortured to a point he where he couldn't take it anymore, and finally told the cabin's location. He realized his mistake, and endangered his friends. In order for him to forgive himself, he stays behind. He was already prepared for death to find him.
Look, Sebastian was my favorite character in the show, and it really hurts me to see him die, especially when I wanted to learn more about him. I wrote this in memory of him.
Always thought Sebastian must have a deeply personal reason for risking everything to conspire with Renard against the Royals, living his life in daily extreme peril if his spying was discovered. Wonder what his backstory would be? But I suspect we'll never know why he did all the brave things he did!